Frequently asked questions

Answers from the field.

Honest answers to the questions we hear most often — about OWL EYE® products, services, accuracy, integration and pricing.

All questions

Pick your topic.

Australia & Pacific

What does a stockpile measurement system cost in Australia? ＋
Cost depends on yard size, sensor count and integration scope. Send Equipment Placement your yard layout — you receive a system proposal and budget in AUD within days, with installation and service priced locally from Perth. No obligation.
Who installs and services the system in Australia? ＋
Equipment Placement, our authorised OWL EYE® partner for Australia and the Pacific: Perth headquarters with reach into Darwin, Hobart, Melbourne, Sydney and Brisbane. Site assessment, installation, commissioning, spare parts and scheduled service all run locally — with Sachtleben engineering from Germany connected in the background. ISO 9001 / 14001 / 45001 certified.
Does it survive Pilbara dust, cyclones and coastal salt air? ＋
The sensors are rated −40 to +80 °C with IP65+ enclosures and are hardened inside an active European mining operation. Multi-echo processing separates airborne dust from the material surface — measurement locks onto the stockpile, not the dust cloud. Mounting concepts for cyclone-rated structures and salt-air port environments are part of Equipment Placement's site assessment.
Can it feed train load-out planning and month-end reconciliation? ＋
Yes — that is the core use case for Australian mining: continuous volume and tonnage per stockpile and per zone via calibrated bulk density, streamed into your historian, SCADA or reconciliation workflow through REST API and OPC UA. Every scan is stored as a 3D block model with full history, so month-end numbers come from measurement, not estimation.
How fast can a system be installed on an Australian site? ＋
Typical projects run: site assessment by Equipment Placement, then hardware delivery pre-configured from Germany, then mechanical/electrical installation and commissioning by the Perth team — usually within days on site once mounting and power are in place. Wireless bridges avoid most civil works for cabling.
Why stationary LiDAR instead of drone surveys? ＋
Drone surveys are snapshots: valid for the flight day, repeated cost per flight, and grounded by weather and site flight restrictions. Stationary 3D LiDAR measures continuously — every shift sees current numbers, day and night, with no pilot and no flight approvals. For yards measured monthly or more often, continuous measurement is cheaper per data point and audit-consistent.
Does it work for grain bunkers and open bulk storage? ＋
Yes — open grain bunkers, bunker tarps off or on harvest flow, fertiliser sheds and sugar terminals are classic applications. The sensors measure the surface regardless of commodity; tonnage runs via calibrated bulk density per grade. For harvest-season peaks the system tracks intake and outloading continuously — no walking the bunker, no survey backlog at receival sites.
Is the system compliant with Australian standards (AS/NZS)? ＋
Installation is engineered against your site's AS/NZS electrical and safety regime by Equipment Placement — they hold ISO 9001, 14001 and 45001 and handle the local certification path natively, so your safety officer signs off the install without a paper chase to Germany. Sensor enclosures are IP65+ rated, low-voltage, laser class 1 (eye-safe).
Does it work on remote mine sites with limited connectivity? ＋
Yes. Processing runs on site — the system does not need a permanent cloud connection to measure. Dashboards and APIs serve locally into your site network; wireless bridges avoid long cable runs across the yard. Where WAN links exist (even low-bandwidth), remote support and reporting run over them; where they do not, data stays available on site.
How large a stockyard can the system cover? ＋
There is no practical upper limit — coverage scales by adding sensors with overlapping scan cones. Detection range is 5–200 m per sensor, so Pilbara-scale yards with long stacker lines are covered by a sensor row along the yard axis; small quarry yards often need just one or two units. Equipment Placement's site assessment determines the sensor plan.
Is the measurement audit-grade for stocktakes? ＋
Every scan is stored as a 3D block model with full history, and volumes are computed against a surveyed base plane — repeatable, documented and independent of who pushes the button. Operators use it for month-end and year-end stocktakes and for reconciliation against weightometer and dispatch figures; where an independent one-off verification is wanted, a survey-grade terrestrial laser scan can complement it.

Bulk Inventory & Stocktaking

How does a cut-off-date stocktake for bulk materials work with laser scanning? ＋
In a cut-off-date stocktake — such as the year-end inventory on 31 December — the complete stock is captured on one fixed date. With terrestrial laser scanning, our team brings a Riegl VZ-1000 (1,200 m range, 8 mm precision) to your site; the whole yard is scanned within a few hours — no production stop. From the point cloud we derive per-pile volumes (m³, and tonnes via bulk density), a contour plan and a signed measurement protocol — a stock survey at >99 % accuracy, delivered in two working days. We operate across the entire DACH region — Germany and Austria directly, in Switzerland also through our partner Pontax. Details: bulk inventory service; if you need stock figures continuously rather than on a survey date: stationary stockpile monitoring.
Is laser-scan stocktaking recognised by financial auditors? ＋
Yes. The signed measurement protocol documents the instrument, calibration, scan positions and processing chain in a traceable way — which is why laser-scan bulk stocktaking is recognised by financial auditors as evidence of stock and is used by trading houses, port operators and audit firms across central Europe. Compared with estimating or pacing out, the survey delivers >99 % accuracy and is archived audit-proof. Typical occasions: year-end inventory, audit verification, M&A due diligence, customs and tax inventories, insurance claims. Details: stockpile survey & bulk inventory.
Can a laser-scan stocktake be used for inventory verification and collateral monitoring? ＋
Yes — that is one of its main uses. When banks or trade financiers lend against bulk material stock (pledged goods), they need independent, repeatable evidence of what is actually in the yard. A terrestrial laser-scan stocktake delivers exactly that: inventory verification with 99 %+ volume accuracy, a signed measurement protocol with instrument, calibration and scan positions documented, and a 3D point cloud as evidence — auditor-recognised and independent of the borrower's own figures. For recurring collateral monitoring, the survey can be repeated at fixed intervals — or replaced by stationary LiDAR monitoring that reports stock levels continuously. Details: bulk inventory service.

OWL EYE® Bunkers & Feeders

What is 3D level measurement — and how does it differ from radar? ＋
3D level measurement means that instead of measuring the fill level at a single point (as radar, ultrasonic or plumb-bob sensors do), a LiDAR sensor captures the entire bulk material surface as a 3D model. From that the system computes the true volume — even with material cones, ratholes above the discharge and uneven filling, where a point measurement is systematically wrong: the probe sees the tip of the cone or the hole above the outlet, never both. The other key difference: a radar probe delivers one height; 3D level measurement delivers volume, fill-level distribution and free capacity per zone — contactless, wear-free and dust-resistant through multi-echo processing. Details: OWL EYE® BUNKERS & FEEDERS — 3D level measurement for silos & bunkers; for waste bunkers in incineration plants: waste bunker monitoring.
Which container types work with OWL EYE® Bunkers & Feeders? ＋
Silos, hoppers, crushers, charging hoppers, mixer feeders, process vessels, containers and pusher-floor systems. The 3D-LiDAR sensor mounts on the lid or upper structure and looks down onto the bulk surface — anything with an accessible top opening can be measured. LiDAR range is 0.5–40 m, so the system covers everything from shallow feed bunkers up to tall storage silos. Optional compressed-air auto-cleaning keeps the optics clear in dust- or vapour-heavy environments like cement, charcoal or sugar receiving.
Which bunker and silo geometries are supported? ＋
Cylindrical silos, rectangular bunkers, conical hoppers, slot bunkers, flat-bottom containers — any vessel where a top-mounted scanner has a clear view of the material surface. Single-point fill-level (TOF / radar replacement) starts at 0.5 m diameter; full volumetric mode for irregular bunkers (e.g. feeder bunkers with a sloped bottom) needs ≥ 1.5 m clearance for the scan cone. Maximum measured depth is typically 30 m, beyond that the signal-to-noise drops below the ±2% spec.
How does the sensor cope with dust, condensation and corrosion? ＋
The OWL EYE® BUNKER housing is IP65-rated stainless steel or coated aluminium with an optical window that can be cleaned by an optional compressed-air pulse on a schedule (every 30 min in dusty environments). For aggressive atmospheres (chloride, acid vapours, sugar dust, salt) we ship a corrosion-resistant version. Internal heater + dew-point control prevents condensation in cold storage buildings. Maintenance interval: 6-month sight check, yearly window cleaning.
Why measure bunker and silo fill level without a mechanical probe? ＋
Mechanical fill-level devices — level cables, plumb-bobs, rotating paddles, capacitance rods — all share one problem: a part sits in the material. That part abrades, gets buried under an inflow, jams when material is sticky, and needs regular maintenance. And it still only reads one point. Non-contact 3D-LiDAR fill-level measurement works the other way round. The sensor sits above the material and never touches it — nothing to wear, nothing to bury, nothing for sticky or moist bulk to cake onto. Instead of one point it scans the whole surface, so it captures the real volume across cones, funnels and irregular shapes, and flags wall buildup or bridging. For silos, feed bunkers, crushers and process vessels that means: contactless, maintenance-free, dust-resistant, and a true 3D fill level rather than a single-point guess. OWL EYE® BUNKERS & FEEDERS is built around exactly this principle.
Can OWL EYE® scan buckets, hoppers and chutes for fill levels? ＋
Yes. OWL EYE® BUNKERS works on any open or partially open vessel where a 3D-LiDAR can see the bulk surface — and that includes buckets, hoppers, charging chutes and intermediate bins, not only large silos. Typical bucket-scan installations:
  • Charging hoppers and feed buckets — fill volume captured continuously, so the upstream feeder can be paced to actual demand.
  • Crusher and mill feed hoppers — choke-feed monitoring; OWL EYE® flags partial fill or bridging before throughput drops.
  • Mobile and movable buckets — mounted sensor scans the bucket position-by-position; volume is computed against the known bucket geometry.
  • Chutes and intermediate bins — anti-blockage monitoring; profile irregularities show bridging or arching long before the chute clogs.
Mounting height typically 0.5 to 5 m above the opening. The sensor is calibrated against the empty-vessel geometry on commissioning, so fill volume is the live difference between current and empty surface. Sensor type, range and protection class are selected from the OWL EYE® multi-vendor portfolio to match the duty (mining-grade rugged, food-grade hygienic, etc.).

Comparison

When is Radar actually a better choice than LiDAR? ＋
Three clear cases. (1) Permanent heavy dust — cement clinker bunkers, coal silos with constant dust circulation. LiDAR's optical window blinds within hours; Radar sees through. (2) Single-point fill-level only — you don't need surface shape, just average height. Radar is simpler, cheaper to maintain. (3) Very long ranges (>300 m) — LiDAR signal-to-noise drops; Radar maintains useful return at km-scale. For everything else — clean indoor storage buildings, multi-zone piles, billing-grade accuracy, conveyor cross-sections, truck-load shapes — LiDAR's resolution wins by an order of magnitude.
Stockpile measurement vs stockpile monitoring — what's the difference? ＋
Stockpile measurement is a single capture event with a numeric result — volume in m³, tonnage in t, signed report. It answers the question: "How much is in this pile right now?" Manual surveys, drone flights and terrestrial laser scans are all measurements. They are point-in-time snapshots. Stockpile monitoring is a continuous stream of measurements over time, with trend, FIFO aging, dead-inventory detection and alarms. It answers: "How did this pile evolve over the shift, the week, the year — and what should we do next?" Periodic measurement is enough for audits, year-end stocktaking or due diligence. Continuous monitoring is required for operational decisions: dispatch planning, reclaim sequencing, throughput reconciliation against weighbridge tickets, alarm on overfill or unexpected reclaim. OWL EYE® STOCKPILE delivers both on the same platform: each individual scan is a fully signed measurement with ±1% accuracy, and the time-series of those scans — archived as 3D block models — is the monitoring layer. Customers run it 24/7 in live mode or on a schedule (per shift, per hour). For one-off survey-grade audits we additionally offer Bulk Inventory with a terrestrial Riegl scanner.
Doesn't dust kill LiDAR? How do you handle dusty environments? ＋
Dust degrades LiDAR but rarely kills it. Three layers of mitigation: (1) Multi-echo signal processing — modern industrial LiDAR returns multiple echoes per pulse and the algorithm picks the right one (the dust echo gets filtered out). (2) Optical-window cleaning — once-a-year visual inspection in normal industrial settings, every 6 months in dustier ones. (3) Compressed-air auto-cleaning — optional pulse on the window every 30 min, available on all OWL EYE® platforms for very dusty installations (cement, salt, fertilizer). In our experience: LiDAR works fine in 90 % of "dusty" industrial environments. The 10 % where it doesn't are the cases where Radar legitimately wins.
What about ultrasonic sensors? They're cheaper. ＋
Ultrasonic is fine for single-point fill-level in small vessels (under ~10 m, calm material, no temperature gradients). It fails on every dimension that matters for industrial bulk-material monitoring: range maxes out around 10-15 m, accuracy is ±5-10 % on uneven surfaces, dust and vapour scatter the sound waves, and there's no surface-shape information at all — just one average distance. Cost is the only LiDAR-vs-ultrasonic argument. For one small dosing hopper at €500 it's the right call. For anything stockpile-scale, the price difference is dwarfed by the inventory error you accumulate over a year.
How does LiDAR compare to a belt scale? ＋
Different jobs. A belt scale measures mass flow at one specific belt — accurate to 0.5-1 % when calibrated, but only at that point and only for the moving material. LiDAR measures volume in any geometry: stockpiles, bunkers, trucks, plus the cross-section of moving belts. In practice they complement each other. The belt scale is your reference for material on a single belt. LiDAR gives you stockpile inventories, bunker fill, truck-load profiles, multi-belt overview, and FIFO tracking — none of which a belt scale can do. Sachtleben uses both: LiDAR for everything stationary or geometric, belt scales as a periodic re-calibration reference for the LiDAR mass output.
How does LiDAR compare to a drone survey for stockpiles? ＋
Different jobs. A drone survey produces a photogrammetric point cloud from a single flight — accurate to 1–3 % with a surveyed network of ground control points and 3–5 % without, but only at that moment, only when weather and airspace cooperate, and only with a certified pilot on site. Stationary LiDAR like OWL EYE® STOCKPILE measures continuously, 24/7, in rain, dust, snow, fog and at night — no pilot, no airspace permit, no weather window. Each scan updates per-pile volume in the dashboard within minutes, so the operations team and finance work from the same live number. In practice: drones make sense for one-off as-built surveys or vast remote sites without infrastructure. For any yard where the volume number drives daily dispatch, reconciliation or contract release, continuous LiDAR is the right call. See LiDAR vs drone for stockpile monitoring for the full side-by-side.
Why not just stick with manual surveying or drone flights? ＋
Frequency and cost. A manual survey or drone flight gives you a snapshot — accurate (we offer it as a service ourselves), but valid only for the moment of capture. The next morning, after a shift of intake and reclaim, your inventory is wrong again. Permanent LiDAR gives you the same accuracy continuously, every 5 minutes if you want, around the clock. For a typical mid-size industrial site that runs 200+ shifts per year, the case for permanent LiDAR is not the price of the surveys it replaces — the inventory is usually surveyed one to four times a year — but the time between them, when inventory discrepancies of typically 2–4 % against book stock go unseen. Plus you get FIFO tracking, alarms, and shift-by-shift reporting that periodic surveys can't deliver at any cost.
How does LiDAR compare to a weighbridge for truck dispatch? ＋
For dispatch, the comparison is one-sided. A weighbridge produces one mass number per truck after a 30–60 s stop-tare-ticket cycle, and tells dispatch nothing about how the truck is loaded. A LiDAR drive-through gantry produces a full 3D load shape in 8 s: volume, per-zone fill, centre of gravity and an under-/over-fill flag — all delivered while the truck is still under the gantry. In practice this means LiDAR catches problems the weighbridge cannot see at all: a truck whose volume is correct but whose density is wrong (mixed material), a tipper loaded heavily on one side, a partial fill that the contract penalises. Dispatch decides at the gantry exit, not after the truck has already left the yard. The full side-by-side data table is on the LiDAR vs weighbridge page.
What is the throughput advantage of LiDAR vs a weighbridge? ＋
A single weighbridge with a stop-tare-ticket cycle of 30–60 s clears ~60 trucks per hour at peak — and that is a clean theoretical peak; real operations with a queue and ticketing fall well below it. A two-lane OWL EYE® Truck Terminal gantry, drive-through at 5 km/h with an 8 s scan, sustains 200+ trucks per hour. The throughput gap matters most during shift-change peaks at quarries and recycling yards, where a queueing weighbridge becomes the bottleneck for the entire site. The LiDAR gantry removes that bottleneck without adding personnel — drive-through means the driver does not leave the cab, no operator ticket, no scale-house manning. The full throughput line is in the LiDAR vs weighbridge data table.

Dead Inventory & FIFO

What is dead inventory and how does continuous LiDAR monitoring fix it? ＋
Dead inventory is bulk material that sits at the back or bottom of a pile for months because reclaim always happens from the same side. It ties up working capital, ages out of spec (caking, moisture, oxidation) and produces unpleasant surprises at year-end physical counts. OWL EYE® STOCKPILE eliminates the blind spot. Every scan cycle is archived as a 3D block model with a timestamp, so the system knows exactly when each cubic metre of the pile arrived. The dashboard colour-codes the pile by age and flags zones that have not moved in 30, 60 or 90 days — real-time monitoring turns a static "dead corner" into a number you can act on, and FIFO reclaim becomes plannable instead of accidental.
How does LiDAR identify FIFO violations in a stockpile? ＋
Every scan cycle is archived as a timestamped 3D block model. The pile is partitioned into operator-defined zone polygons (by product, customer or quality grade), and the system tracks the age of material in each zone — derived from when material first appeared at those coordinates. When reclaim removes volume from a younger zone while an older zone next to it still contains material, OWL EYE® STOCKPILE flags a FIFO violation in real time. The alert names the zone, the age delta and the tonnage moved out of sequence, and is pushed straight to the dispatcher's dashboard and the CMMS. The monthly value-locked report then aggregates violations into a single number for the CFO — including the tonnage at risk of aging out of spec before it is ever touched.

Drone Survey

How much does a drone survey for stockpile measurement cost? ＋
A drone survey including processing costs about €1,200–2,500 depending on the depth of the deliverables, plus travel. The difference lies in the processing scope: pure volume calculation per pile at the lower end — the full package of orthophoto, digital terrain model (DTM), 3D mesh and per-zone stockpile survey at the upper end. Because we offer drone surveying across the entire DACH region with several bases and local pilots, travel costs usually stay small. You receive a binding fixed-price quote up front, typically within two working days. Details: drone surveying & aerial survey; if you need inventory figures for same-day decisions rather than for the accounts, stationary LiDAR is the right tool — not because each measurement is cheaper, but because it closes the gap between surveys.
How accurate is a drone survey of stockpiles? ＋
±2 % volume accuracy at 2 cm ground sample distance (GSD). RTK-GNSS plus ground control points georeference every flight to 2 cm absolute accuracy in your coordinate system; high-overlap photogrammetry delivers a dense point cloud, orthophoto and digital terrain model. That puts drone surveying on par with classic ground surveying — but a 30-minute flight covers 5 hectares, including piles you cannot even reach on foot. On the market, the typical volume accuracy of a drone survey is 1–3 % with a surveyed ground-control network and 3–5 % without, depending on image overlap; our RTK flights reach ±2 % at 2 cm GSD. For comparison: stationary LiDAR measures at ±1 % — continuously instead of on a survey date. When each method pays off: LiDAR vs drone; the flight service itself: drone surveying.
What can a drone survey be used for? ＋
A drone survey with RTK photogrammetry covers five use cases — from a single flight: stockpile volume measurement and quantity surveys (per-pile volume at ±2 %, mass via bulk density), pit and quarry scans (overburden cubage, terrain profiles, as-planned vs. as-built), route and corridor surveys (longitudinal and cross profiles for earthworks and conveyor routes), building heights and building surveys (heights, roof and facade areas) and elevation mapping for construction sites (DTM/DSM per construction stage, progress documentation, earth-mass balance). Every survey delivers orthophoto, terrain model, point cloud and the requested analyses — typically €1,200–2,500 incl. processing. Details: drone surveying.

OWL EYE® Filling Terminal

What is the OWL EYE® Filling Terminal? ＋
OWL EYE® Filling Terminal is an industrial 3D-LiDAR system that measures the load volume in a truck while it is being filled — under a silo or loading spout, or by wheel loader beneath a mast. Its purpose is to prevent the truck from being overloaded or overfilled. The sensor sits above the loading bay, captures the empty bed first and then follows the rising fill surface, so the operator sees the volume in m³ live and loading stops at the target volume. At constant bulk density the loading is measured to ±0.5 t. Weighing and billing stay on the weighbridge. The truck is identified by number plate or RFID, and every loading is booked to the ERP. To measure the finished load in a drive-through pass instead, see OWL EYE® Truck Terminal.
Can loading stop automatically at a target volume? ＋
Yes. A target volume is set per order or per truck. When the live volume reaches it, OWL EYE® sends a signal via OPC UA or REST to the loading control — for example to close the spout — or shows it on the operator display at the loading point. The operator stays in charge: whether the signal closes the spout directly or prompts the operator is decided per site, together with your automation team.
Does it work for wheel-loader loading as well as a silo spout? ＋
Yes. For wheel-loader loading the sensor sits on a mast at the loading bay and looks into the truck bed. Every bucket that is tipped raises the measured surface, so the volume in the bed grows bucket by bucket and the loader driver sees how much is still missing to the target. Under a silo or loading spout the principle is the same — the material simply arrives as a continuous stream instead of in buckets.
Which trucks can be measured? ＋
All trucks with an open top: tippers, open bulk trailers, walking-floor trailers and dump trucks. The sensor has to be able to see into the bed. Closed pneumatic silo tankers cannot be measured: they are filled through a closed hatch, so the fill surface is not visible.
Does it replace the weighbridge or loading scale? ＋
No — you still need the weighbridge or loading scale. It weighs the truck and remains the certified reference for billing (legal-for-trade weighing). The Filling Terminal has a different job: it measures the volume live during loading and so prevents the truck from being overloaded or overfilled. The scale weighs and bills; the Filling Terminal makes sure the truck arrives there correctly loaded.
How accurate is the measurement during filling? ＋
At constant bulk density the Filling Terminal measures the loading to ±0.5 t. The LiDAR measures the volume in the truck bed; the tonnage is that volume multiplied by the bulk density of the material, which is calibrated per material. As long as the density stays constant, the accuracy in tonnes holds. If moisture or grain size vary, the bulk density changes — and with it the tonnage derived from the volume. The site survey at your loading point confirms the installation geometry: spout or wheel-loader loading, sensor position above the bay and dust during filling. Your loading scale or weighbridge remains the legal-for-trade mass reference.
Filling Terminal or Truck Terminal — which one fits? ＋
Filling Terminal measures during loading, at the loading point — it lets you stop at the target volume. OWL EYE® Truck Terminal measures the finished load in a drive-through pass after loading, for example at the gate or beside the weighbridge. To load correctly in the first place, the Filling Terminal is the right tool; to check what leaves or arrives at the site, the Truck Terminal. Both run on the same software and can be combined on one site.

General

What is OWL EYE® and what does it measure? ＋
OWL EYE® is an industrial 3D-LiDAR platform for measuring volume, mass and flow of bulk materials. It covers six scenarios from one software stack: stockpiles in storage buildings and outdoor yards, conveyor belts, drive-through truck terminals, silos and bunkers, and mobile units mounted on wheel loaders or excavators. Every variant shares the same dashboard, the same REST / OPC UA / SAP interfaces and the same calibration chain — so you can start with one belt or one pile and grow into a site-wide measurement system without changing software.
What are the methods for bulk volume measurement? ＋
Four methods dominate bulk volume measurement in industry, each with a clear sweet spot: (1) Manual surveying — tape, rod, total station. Cheap per measurement, but slow, requires the area to be shut down, and accuracy depends on the surveyor. Typical ±2-3%. Useful only for very infrequent audits.
(2) Drone aerial photogrammetry — a UAV flies the yard and reconstructs surfaces from overlapping photos. Fast for open outdoor piles, but weather-bound, restricted in many sites, and accurate to 1–3% with ground control and 3–5% without. No indoor coverage and no continuous data.
(3) Terrestrial laser scanning — a survey-grade scanner (e.g. Riegl VZ-1000) reaches >99% accuracy, but the operator must visit site for every capture. Best for year-end stocktaking, due diligence, or trade verification.
(4) Fixed LiDAR — permanently mounted overhead 3D-LiDAR delivers continuous ±1% volume readings 24/7, indoor or outdoor, through dust. The only method that supports operational decisions in real time. OWL EYE® covers all four. OWL EYE® STOCKPILE is the fixed-LiDAR system for continuous monitoring; Bulk Inventory is the terrestrial-scan audit service; Drone Survey is the aerial option for one-off yard captures. The right method depends on how often you need the number and what tolerance the downstream process requires.
Which materials can OWL EYE® measure? ＋
Practically every bulk material that sits, falls or flows. In production today: salt and potash, coal and coke, iron ore, copper ore, bauxite, limestone, cement, quarry stone and aggregates, wood chips, pellets, biomass and charcoal, sugar beets and grain, and various recycling streams. Material colour, grain size and moisture do not affect the LiDAR signal in any meaningful way — every site is calibrated for material density during commissioning so that volume in m³ becomes mass in tonnes automatically.
How accurate is OWL EYE®? ＋
All stationary OWL EYE® systems — Stockpile, Truck Terminal, Volume Flow, Bunkers & Feeders and Mobile Mapping — deliver ±1% volumetric accuracy under industrial conditions, after on-site calibration. That figure is field-measured at active sites (K+S, proFagus, Nordzucker, Aurubis, Sachtleben Minerals), not a lab spec. For one-off audits we also offer the Bulk Inventory service: a survey-grade Riegl VZ-1000 terrestrial scanner reaches >99% volumetric accuracy with 8 mm distance precision at 100 m. Use it for year-end stocktaking, due diligence or trade verification.
What is the lifespan and warranty of an OWL EYE® sensor? ＋
OWL EYE® uses solid-state LiDAR sensors — there are no rotating mirrors, no mechanical scanning parts and no contact with the bulk material. That removes the components that usually fail first in industrial measurement hardware, so the practical service life is long: the sensors are built for continuous 24/7 operation across a −40 °C to +80 °C range. Every installation comes with a manufacturer warranty on the hardware; the exact term is stated in your project quote. Because the system has no wear parts, there is no scheduled mechanical maintenance — cleaning of the sensor window in dusty environments is the only routine task, and the dashboard flags when signal quality drops. An optional service contract adds remote monitoring, firmware updates, calibration checks and a guaranteed response SLA. Many customers run this so the OWL EYE® team spots a drift or a dirty window before it affects production data. For exact warranty terms and expected service life for your sensor configuration, ask us at info@sachtleben-technology.com.
Is OWL EYE® suitable for ATEX / explosive-atmosphere zones? ＋
Many bulk materials — grain, sugar, wood pellets, certain ores and chemicals — create dust that can form an explosive atmosphere. Whether a measurement device may be installed in such an area depends on the ATEX zone classification of the specific location (Zone 20 / 21 / 22 for dust, Zone 0 / 1 / 2 for gas), which is defined in your site's explosion-protection document. For installations in or near a classified zone, OWL EYE® offers an Ex-protective enclosure for selected sensors — the sensor sits inside the enclosure and scans through it, so the measurement runs without exposing the electronics to the explosive atmosphere. Not every sensor in the portfolio has an Ex-enclosure option, and the zone it is suitable for depends on the specific configuration. We therefore review your zone classification with you per project and determine the correct approach for that exact mounting position — an Ex-enclosed sensor inside the zone, or a standard sensor placed outside the rated zone with a clear line of sight into it. If you have an ATEX-classified area, tell us the zone and the material when you get in touch — write to info@sachtleben-technology.com. We will confirm in writing what is and is not possible for your specific situation before anything is quoted.

Installation & support

How long does installation take? ＋
It depends on the solution. Typical commissioning windows from our reference projects: - OWL EYE® Volume Flow — hours per belt (sensor mounting + calibration in a single visit). - OWL EYE® Stockpile — under two weeks, including hall survey, sensor planning, mounting and PLC/network integration. - OWL EYE® Truck Terminal — under a week of on-site work, plus the gantry foundation lead time; total project typically under three weeks. Every package includes onboarding for your team, documented interfaces, predictive maintenance and 24/7 remote support.
Can OWL EYE® integrate with our SAP / ERP / PLC systems? ＋
Yes. Every OWL EYE® variant ships with the same integration toolkit: REST API, OPC UA, native SAP integration and analog signals (4–20 mA) for legacy PLC environments. Volume, mass, fill level, throughput and threshold alarms can be pushed into the systems you already operate — no proprietary middleware in between. The software runs container-based with documented interfaces, so your IT team can deploy it on premise, in the DMZ or in a private cloud. All variants share the same dashboard and the same APIs, so adding a second sensor type later does not mean a second integration project.
Can OWL EYE® be retrofitted onto an existing PLC without involving our IT department? ＋
Yes. OWL EYE® runs as a self-contained edge system: the sensor and a local processing unit do all the measurement and calculation on site, without needing a connection to your corporate IT network. For a PLC retrofit, the OWL EYE® edge unit delivers the measured values straight to your control system over the industrial protocols a PLC already speaks — OPC UA, Modbus TCP, or potential-free / analogue outputs. That is an automation-side connection handled by your process or electrical team; it does not touch the office network, so no IT-department onboarding, no firewall change request and no corporate-network security review are required. If you later do want the data in SAP, a cloud dashboard or an MES, that integration can be added on top — but it is optional and entirely separate from getting live values into the PLC. Plenty of customers start with the PLC-only retrofit and add higher-level integration months later. Tell us which PLC and which protocol you use at info@sachtleben-technology.com and we will confirm the exact wiring and data points for your setup.

Material Balance & Reconciliation

How does OWL EYE® close a material balance gap? ＋
A material balance gap is the unexplained delta between what was booked in (feed, deliveries) and what was booked out (production, shipments, recorded stock). It usually traces back to stock-on-hand being a guess: belt scales measure flow at one point, but the pile in between is estimated. OWL EYE® closes the loop on the stock layer. Continuous 3D-LiDAR coverage of every stockpile and bunker delivers a real volume — and, with material density, a real tonnage — at the same timestamp you cut the period. In the reconciliation ledger, the unexplained loss column shrinks because the opening and closing inventory are measured, not booked. Remaining discrepancies are then traceable to belt-scale drift, moisture or sampling error — and can be addressed instead of being written off as "shrinkage".
What is mine-to-mill reconciliation and how does LiDAR help? ＋
Mine-to-mill reconciliation is the practice of comparing what the geological block model predicted (grade, tonnage) with what actually arrived at the mill — pit, crusher, ROM stockpile, mill feed — to verify recovery and grade-control performance. The weakest link is almost always the ROM stockpile: trucks tip in, the reclaimer pulls out, and the in-between tonnage is back-calculated. OWL EYE® STOCKPILE measures the pile directly. Each shift, the dashboard reports the actual tonnes on the pad, the tonnes added, and the tonnes drawn down. Combined with belt-scale data on the mill feed and crusher infeed, the reconciliation ledger becomes fully measured — no estimated stock terms. Variances against the block model are then real signals about dilution, grade control or recovery, not artefacts of unmeasured inventory.

OWL EYE® Mobile Mapping

How does Mobile Mapping work without a survey crew? ＋
The 3D-LiDAR + GNSS/SLAM unit is bolted directly onto the cab roof of your wheel loader, excavator or dump truck. The machine works as normal — every drive between piles becomes a fresh measurement pass, and the system stitches the point clouds into a continuously-updated 3D yard model in the background. Outdoors the unit uses RTK-GPS for centimeter-precise positioning. Indoors, where there is no GPS, it switches to SLAM (simultaneous localisation and mapping) using the LiDAR itself. Same hardware, same dashboard, no operator change in workflow.
Which vehicles can be equipped with OWL EYE® MOBILE MAPPING? ＋
The standard kit (3D-LiDAR + GNSS + IMU + edge computer) is designed for wheel loaders and excavators in the 5-50 tonne class — Caterpillar, Komatsu, Volvo, Liebherr, Hitachi etc. We've also installed it on dump trucks, telehandlers and even a UTV for survey work. The mounting bracket is custom per machine model; the rest of the hardware is identical across vehicle types. Power: standard 12 / 24 V from the cab — no extra battery needed.
How accurate is mobile mapping indoors without GPS? ＋
Indoors the system switches from GNSS to SLAM (simultaneous localisation and mapping) using the LiDAR itself as the positioning reference. Typical drift is below 0.5% per 100 m of travel, which translates to a volume accuracy of ±2-3% across a normal warehouse. With known ground-truth markers (e.g. corner targets in the storage building) we pin the SLAM solution to <0.1 m and reach the same ±1% as the outdoor RTK-GPS mode.
Which vehicles can OWL EYE® mobile LiDAR be mounted on? ＋
The standard OWL EYE® mobile LiDAR kit (3D-LiDAR + GNSS + IMU + edge computer) is designed for the working fleet found at almost every bulk-material site. Most common: wheel loaders in the 5–50 t class (Caterpillar, Komatsu, Volvo, Liebherr, Hitachi) with the cab-roof clamp. Underground: LHD / load-haul-dump scoops (Sandvik, Epiroc, Caterpillar) running in pure SLAM mode where there is no GPS. We have also installed the same kit on excavators for stationary survey work from the boom, on dump trucks for haul-road tracking and bench-face capture, and on telehandlers and UTVs for one-off campaigns. The mounting bracket is custom per machine model; the rest of the hardware is identical. Power: standard 12 / 24 V from the cab — no extra battery, no civil works, no rebuild.
How is wheel-loader scanning different from a stationary stockpile scan? ＋
A stationary stockpile scan (our OWL EYE® STOCKPILE solution) uses fixed LiDAR sensors mounted on masts or walls. Field of view is constrained to what each sensor can see from its post — perfect for piles that stay in roughly the same place, but blind to whatever sits behind another pile or outside the cone. A wheel-loader scan moves the sensor with the machine. Every drive between piles sweeps a new viewing angle, so the 3D yard model rebuilds itself from many vantage points — no shadowed zones, no fixed coverage geometry, no civil works for masts. The trade-off: the model updates on machine activity, not continuously. A loader sitting idle does not refresh its pile. Most large yards run both: fixed sensors on the high-value primary piles (continuous, real-time), wheel-loader LiDAR for the rest of the site (full coverage, no civil works). Same dashboard, same ERP feed, same volume figures.

Industrial Perception AI

What does custom perception AI software cost? ＋
We don't publish list prices because every project is scoped against your data and your decision logic — but we work to three predictable tiers. Discovery & Assessment — a 1–3 day workshop, on-site or remote, fixed price in the low-four-figure range. You receive a written feasibility note, a recommended next step and (if applicable) a fixed-price quote for the follow-on project. Useful even if you don't then go ahead — many customers use the note to evaluate two or three vendors. Custom Pipeline / Tool — a 4–12 week project delivering a working perception pipeline (parser + algorithm + dashboard or OPC UA integration). Fixed scope, fixed price, you own the code at handover. Typical project size is in the mid-five to low-six-figure range depending on data volume, sensor count and integration depth. Long-term Partnership — a monthly retainer for ongoing development and on-call support. Sized to the team capacity you need (typically 0.5–2 FTE equivalent). Quarterly road-mapping included. All three tiers include source code, written documentation and a clean handover — no licence dependence on us. See our Industrial Perception AI service for the full engagement model.
How long does it take to build a custom perception pipeline? ＋
From signed contract to a working tool in production, expect 4–12 weeks for a standard custom-pipeline engagement. The spread is driven by three factors. Data readiness. If you already have labelled data or representative recordings, we start training in week 1. If we need to set up data collection, add a sensor, or label from scratch, the front end adds 1–3 weeks. Integration depth. A standalone dashboard with REST output is the fastest path — typically 4–6 weeks. OPC UA integration into a running control system, with interlocks, factory-acceptance tests and a customer change-management process, is closer to 8–12 weeks. Sensor count and site complexity. One LiDAR + one camera in a clean indoor environment is faster than a six-sensor outdoor portal with dust, snow and dynamic lighting. We scope the difference up-front in the Discovery workshop. For a faster first signal we recommend the Discovery & Assessment tier — 1–3 days, fixed price, written feasibility note within a week. See Industrial Perception AI for the full model.
Who owns the code and IP we pay you to build? ＋
You do. Our standard contract transfers full ownership of the project-specific code, model weights, training data (where the data is yours) and documentation to you on final acceptance. We don't keep a back-door licence and we don't lock you into a maintenance contract. What we retain is our pre-existing toolbox — reusable libraries, calibration utilities, generic data parsers, the OWL EYE® core — which we license to you, royalty-free, for use on the delivered tool. This is the same boundary that any reputable engineering firm draws: we bring the toolbox, you keep the deliverable. If you want a different IP arrangement — for example a joint patent on a novel algorithm, or a co-developed model that we both reuse with consent — we structure that explicitly in the project contract. Tell us up-front in the Discovery workshop. Full engagement details on our Industrial Perception AI page.
Can you use our existing cameras and LiDAR sensors? ＋
Yes — in most cases. Our toolchain is sensor-agnostic on the data layer. If your sensors deliver a standard format (PCD, LAS, E57 for point clouds; RTSP, GigE Vision, USB3 Vision for cameras) we can ingest them in a day. We've worked with Riegl, Livox, Faro, Hesai, Velodyne, Ouster, Basler, FLIR, Allied Vision and IDS cameras. We'll tell you honestly when the existing hardware isn't the right tool. Common cases where we recommend a replacement: - The existing LiDAR is too narrow (FoV or range) to cover the area you want classified — usually solved by repositioning before buying anything new. - The camera is auto-exposing on a high-contrast scene (sun + shadow at a gate), which breaks classification reliability — solved by switching to a manual-exposure industrial camera with HDR sensor. - The existing sensor's vendor lock-in (proprietary stream format, no documented SDK) makes integration cost more than a Livox replacement. We don't earn a margin on reselling hardware to you. If you do want us to source new sensors, we do that through our normal Hardware & products channel at list price. See Industrial Perception AI for how we scope it.

Pricing & contracts

How is pricing structured? ＋
Hardware plus installation as a one-off project price, plus an optional service contract for ongoing remote support and SLA. That's it — no per-measurement fees, no per-user dashboard licensing. We don't publish list prices because every site is genuinely different: sensor count depends on storage-building geometry, integration scope depends on your IT landscape, and calibration depends on the materials. Drop a line at info@sachtleben-technology.com with a few words about your site — we typically come back with a detailed proposal within one business day.
What are typical hardware costs? ＋
Hardware is project-priced, because the capex driver is sensor count — and that depends on site geometry, not a price list. As a rule of thumb: a single-belt Volume Flow installation uses one 2D-LiDAR sensor and sits in a different order of magnitude from a large outdoor stockpile or multi-bay storage building, which may need several 3D units to cover the geometry without blind spots. ATEX housings and harsh-environment enclosures add to the bill of materials. Tell us about your site at info@sachtleben-technology.com — we typically return a detailed proposal within one business day.
What is included in the price? ＋
The project price bundles hardware plus installation as a one-off — turn-key, not a box of sensors. Included in every project:
  • Site survey and sensor-layout planning
  • Mounting structures, cabling and commissioning
  • Material calibration for your specific bulk goods and density range
  • Integration into your SCADA, SAP, MES or DCS landscape with custom data points
  • Dashboard access — no per-user licence fees
Standalone dashboards are simpler than a full ERP/MES tie-in, and calibration time scales with the number of materials — both are reflected in the proposal.
Are there recurring fees after installation? ＋
There are no per-measurement fees and no per-user dashboard licences. After commissioning, the system runs on the hardware you already own. The only optional recurring cost is a service contract for ongoing remote support and SLA — covering monitoring of sensor health, firmware updates, recalibration if your material mix changes, and prioritised response times when something needs attention. Customers typically take the service contract when the OWL EYE® readings feed safety logic, fiscal weighing or month-end ledger close, where unattended sensor drift would be expensive. For non-critical sites it is genuinely optional.
What is the typical ROI and payback period for OWL EYE®? ＋
Most installations pay back within 12 to 24 months, depending on what the volume number replaces. The fastest paybacks (under 12 months) are sites where the LiDAR signal removes a recurring cost — manual climb-and-tape inventories, demurrage on truck queues at a weighbridge, or month-end stock take that stops production. The next bracket (12-18 months) is sites where the data unlocks a process gain — fewer over-/under-loaded trucks, fewer overfill incidents on silos, better FIFO control on perishable bulk, less dead inventory at year-end audit. Longer paybacks (18-24 months) are typically pure inventory-accuracy plays where the operational cost was already low. Tell us your case at info@sachtleben-technology.com — we model the payback against your specific replacement cost and current measurement cadence, usually within one business day.

Services

What's the difference between OWL EYE® Stockpile (product) and Bulk Inventory (service)? ＋
OWL EYE® STOCKPILE is a permanent installation: we sell it, mount it on your roof or mast, integrate it with your ERP and you operate it 24/7 from then on. It delivers continuous ±1% volume monitoring with full historical archive — the right answer when you need ongoing inventory. Bulk Inventory is a one-off engineering service: our team comes on site with a survey-grade Riegl VZ-1000 terrestrial scanner, captures every pile in a few hours, and delivers point cloud, contour plan and signed measurement protocol within two business days at >99% accuracy. Use it for year-end stocktaking, audit support or due diligence — and as a reference scan if you're evaluating whether to invest in the permanent product.

Silo Overfill Protection

How does OWL EYE® prevent silo overfill — what thresholds and alerts are supported? ＋
OWL EYE® BUNKERS measures fill level and remaining volume continuously, not as a discrete switch event. That allows configurable thresholds long before a paddle switch would react:
  • Low — material running out, dispatching gets a heads-up; refill triggered or operations notified.
  • High — first warning that headroom is shrinking. Operators can throttle the feed before the dome is reached.
  • Critical — true overfill protection. Hard interlock to the PLC, stops the feed or rejects the next load.
Each threshold is configurable per silo and per material with hysteresis, so normal cycling does not produce alarm storms. Alerts route to OPC UA, REST, MQTT, e-mail or SMS — the PLC contact for interlocked stops is the most common channel. Because the LiDAR captures the entire surface, the system also detects asymmetric build-ups, sidewall caking and hopper-discharge blockages — failure modes a single-point probe cannot see. Silo overfill protection turns from a single switch into a continuous condition signal.
How does LiDAR overfill protection differ from mechanical level switches? ＋
A mechanical high-level switch — rotating paddle, vibrating fork, capacitance rod — gives one binary signal at one fixed height inside the silo. It tells you nothing before that point, nothing about asymmetric build-up on the opposite wall, and nothing about its own state until the next manual functional test. If the paddle jams, the cable corrodes or material cakes around the fork, the silo can overfill silently between two test intervals. OWL EYE® LiDAR overfill protection works the other way round. A 3D-LiDAR sensor mounted above the silo scans the entire bulk surface every second. Three configurable thresholds — low / high / critical — fire on remaining volume rather than on whether one paddle has moved. Bridging, sidewall caking and asymmetric loading are detected as part of the same signal. A heartbeat to the PLC confirms in every cycle that the sensor is alive, so the safety chain is verifiable continuously instead of once a year. For sites where overfill is a real safety case — ATEX dust zones, combustible bulk, downstream cyclone or filter damage — this is the upgrade auditors expect. See OWL EYE® Silo Overfill Protection and the wider BUNKERS & FEEDERS platform.
Is the OWL EYE® silo overfill protection ATEX-certifiable? ＋
Yes. The OWL EYE® silo overfill protection is delivered in hardware variants suitable for ATEX dust atmospheres up to Zone 22 — covering most grain, sugar, charcoal, wood-pellet, biomass and many chemical bulk applications. For sites with Zone 21 requirements or aggressive gas atmospheres we specify the sensor and enclosure per project; not every LiDAR head is certified for every zone, so the safety case is engineered explicitly rather than assumed. The hardware approach has three layers. The optical window is hermetically sealed and rated to withstand the dust loading inside a receiving silo. Wiring options include intrinsically safe loops and barrier-protected supply lines. The enclosure variants are stainless steel or coated aluminium with documented surface-temperature classification, so the assembly fits cleanly into the plant explosion-protection document. On top of the hardware sits a continuous self-test heartbeat into the PLC: every measurement cycle confirms the safety function is active, which is what an auditor actually needs to see in the SIL or proof-test record. Combined with the configurable threshold cascade described on OWL EYE® Silo Overfill Protection and the wider BUNKERS & FEEDERS platform, the result is an overfill safeguard that is both ATEX-suitable and continuously verifiable.

OWL EYE® Stockpile

What is stockpile monitoring? ＋
Stockpile monitoring is the continuous, automated measurement of stockpile volume and tonnage over time. Instead of a single survey on a fixed date, sensors capture the piles again and again — as often as once a minute, once per shift or on a schedule — so inventory, material age and changes are known at any moment, not only at month-end. In LiDAR stockpile monitoring, 3D-LiDAR sensors are fixed to roofs, masts or the building structure. They scan the pile surface; the software turns every scan into a 3D block model and calculates the volume, and a stored bulk density converts it into tonnes. The data feeds dashboards, alarms and ERP/SCADA systems via REST or OPC UA. Drone flights and manual surveys, by contrast, are snapshots: useful for audits, but they do not deliver a continuous signal. OWL EYE® STOCKPILE is a stationary LiDAR stockpile monitoring system with ±1 % volume accuracy, indoors and outdoors. For all methods side by side, see stockpile monitoring systems compared.
What is stockpile cubage (volume survey)? ＋
Stockpile cubage — known as "cubicación de acopios" across Latin American mining — is the calculation of a bulk pile's volume from its geometry to derive tonnage and inventory. Traditionally it is a periodic event: a surveyor with a total station or a drone photogrammetry flight, with results days later that are only valid for the day of measurement. With fixed 3D-LiDAR, cubage stops being an event and becomes a continuous process: sensors above the pile capture the surface 24/7 and the system delivers volume, tonnage and a per-zone 3D model in real time — automatic volume survey at ±1 % accuracy, no drone, no surveyor, no operational stop. Details: OWL EYE® STOCKPILE; for one-off survey-grade audits see the bulk inventory service.
What is volume measurement of bulk material? ＋
Volume measurement of bulk material is the determination of the bulk volume in cubic metres and — via a calibrated material density — the mass in tonnes. It is the basis for inventory, dispatch, material-balance reporting and production control in mining, cement, sugar, wood, salt, recycling and port operations. Four methods compete: manual survey with tape measure and theodolite (slow, inaccurate, hazardous on the pile), drone photogrammetry (1–3 % with ground control and 3–5 % without, weather- and flight-window-dependent), terrestrial laser scanning with a Riegl or Leica scanner (sub-percent accuracy, but as a one-off capture) and stationary 3D-LiDAR multi-sensor arrays (±1 % accuracy, but continuous 24/7). For live inventories and live throughput, only the stationary method is economical. OWL EYE® implements continuous bulk-material volume measurement in four configurations — STOCKPILE for piles, VOLUME FLOW for belts, TRUCK TERMINAL for truck loading and BUNKERS & FEEDERS for silos and bunkers. A one-off high-accuracy stocktake is additionally available via the Bulk-Inventory service with a Riegl VZ-1000 (>99 % volumetric accuracy).
How do you measure bulk material in storage bays? ＋
Measuring bulk material in storage bays means capturing volume and tonnage per bay — despite push walls, partial withdrawals and uneven filling. Stationary 3D-LiDAR sensors on the shed ceiling capture every bay as its own zone: the system knows volume, fill level and material age per bay, at ±1 % accuracy — continuously, not on a survey date. In sheds with a bay layout this is the decisive advantage over drones and manual measurement: no drone can fly safely between push walls, and walking into the bay is slow and risky. The ceiling sensors see every bay permanently from above — including per-bay thresholds (minimum stock, overfill). Details: OWL EYE® STOCKPILE — stockpile and bay monitoring.
How does LiDAR stockpile measurement work? ＋
LiDAR stockpile measurement works in five steps:
  1. Mount: stationary 3D-LiDAR sensors are installed above the pile — on the roof, on masts or on the building structure.
  2. Scan: eye-safe laser pulses capture the entire surface as a dense point cloud, as often as once a minute.
  3. Model: the software merges all point clouds into a timestamped 3D block model.
  4. Calculate: the volume is computed against the surveyed base plane, at ±1 % accuracy.
  5. Convert: a material-calibrated bulk density turns volume into tonnage — per pile and per zone.
The decisive difference from drone flights or walking surveys: this is continuous stockpile volume monitoring, not an on-demand snapshot — every shift sees current numbers, and inventory tracking feeds automatically into your ERP or dashboard. Every step in detail: how OWL EYE® STOCKPILE measures stockpiles; all alternatives compared: 6 stockpile measurement methods.
How real-time is the Stockpile measurement? ＋
OWL EYE® STOCKPILE captures continuously. 3D-LiDAR sensors are permanently mounted overhead — on roofs, masts or building structure — and the dashboard refreshes within seconds of each scan cycle. You can run it 24/7 in live mode or on a schedule (e.g. once per shift, once per hour) depending on how often you need a fresh inventory. Every measurement is archived as a 3D block model, so you also get the full temporal history per pile and per zone — material aging, intake, reclaim and per-shift throughput are queryable backwards in time, not just "right now".
How do you measure stockpile volume without a drone? ＋
Three ways, depending on how often you need the figure. (1) Stationary 3D LiDAR: sensors mounted once — on the roof, on lighting masts or on the building structure — scan the pile surface continuously; the software computes the stockpile volume against a surveyed base plane and converts it to tonnes via bulk density: ±1 % accuracy, indoors and outdoors, up to once per minute, no flight, no surveyor. (2) Terrestrial laser scanning as a service for a one-off audit inventory (better than 1 %, results within days). (3) Classic survey by tape, rod or total station (±2–3 % on cleanly measured piles, 5–15 % for walking surveys and profile estimates). A drone is only a fourth option, for large open yards measured monthly; inside a hall it cannot fly at all. For a continuous stock figure the fixed system is the only method without a recurring cost per measurement — see OWL EYE® STOCKPILE and the comparison LiDAR vs. drone.
What does a drone stockpile survey cost compared with a fixed LiDAR system — and when does the fixed system pay off? ＋
A drone stockpile survey costs roughly €1,200–2,500 per flight including processing (volume per pile, orthophoto, terrain model), plus travel — and every repeat flight costs again. Accuracy with ground control points is typically 1–3 %; flights need daylight, dry weather and open-air yards, and the report arrives days later. A fixed LiDAR system such as OWL EYE® STOCKPILE is a one-off investment: sensors are mounted once, then every scan is free — ±1 % volume accuracy, up to once per minute, indoors and outdoors, 24/7, straight into the ERP. It does not pay off by being cheaper per measurement — the inventory is usually flown one to four times a year — but by closing the gap between surveys: inventory discrepancies typically run 2–4 % against book stock, and moving from 3 % to 1 % saves €20,000–40,000 a year in our cement plant case. Rule of thumb: the number for the annual accounts → drone survey; the number for same-day decisions (reclaiming, blending, loading out, calling off a supplier) → fixed system, with live FIFO and load-out data on top. Real numbers: what stockpile monitoring costs; the flight service: drone survey; the comparison: LiDAR vs. drone.
How do you take a stockpile inventory without stopping the plant? ＋
A stockpile inventory is the count of volume and tonnage of every bulk pile on a given date — for stock balances, accounting valuation and ERP reconciliation. Done by hand, loaders and belts stop while the surveyor measures, and the figure arrives days later. With fixed 3D LiDAR the stockpile inventory runs without stopping the plant: sensors above the yard scan the piles continuously or at scheduled times, at night and without interrupting loading and unloading, and the system delivers volume and tonnage per pile at ±1 % accuracy, 24/7, straight into the ERP. The cut-off date is no longer a shutdown — it is just one more scan. That is how OWL EYE® STOCKPILE works; for a one-off, signed survey-grade inventory see the terrestrial laser scanning service.
How do you measure bulk material with LiDAR? ＋
Measuring bulk material with 3D-LiDAR works on the time-of-flight principle: the sensor emits short laser pulses, measures the round-trip time to the material surface and assembles a dense 3D point cloud. The point cloud is projected onto a known reference geometry — building floor, bunker wall, belt cross-section — and the enclosed volume is computed directly. With a calibrated material density, tonnage falls out in the same step. The method is deployed wherever bulk material is moved or stored: stockpiles in storage buildings and outdoor yards, conveyor belts with cross-belt scanners, bunkers and silos with top-mounted LiDAR, and drive-through truck terminals. Volumetric accuracy in a calibrated installation reaches ±1 %. LiDAR is material-agnostic — it measures salt, sand, ore, wood, cement clinker, sugar or recycling fractions equally well, because the method scans the surface optically and does not depend on conductivity or dielectric constant. Why LiDAR rather than radar, ultrasonic or belt scales is explained at Why LiDAR; the four OWL EYE® configurations under Solutions.
Why fixed sensors instead of drones? ＋
Fixed sensors are always-on. No flight permits, no operator on standby, no weather window — the system measures during night shifts, in rain, inside storage buildings where some drones can't fly. That's why OWL EYE® STOCKPILE installs 3D-LiDAR permanently on roofs, light masts, power poles or building structure: every operational hour produces inventory data. Point cloud data captured with a drone needs to be processed manually by a surveyor to turn into a wire mesh for volume calculations — OWL EYE® STOCKPILE performs this step automatically. Drones still have their place for very large open-air yards or hard-to-reach geometries. We offer that too, as the Drone Survey service — but as a complement to the permanent installation, not a replacement.
What is continuous bulk-material inventory monitoring? ＋
Continuous bulk-material inventory monitoring is the real-time, ongoing capture of stockpile inventories — typically via 3D-LiDAR rather than manual surveys. Unlike an annual stocktake, which only delivers a single snapshot, a LiDAR-based system runs around the clock and updates volume, mass and tonnage every shift. The gap between weighbridge tickets, ERP bookings and physical inventory closes. Compared to walk-arounds, drone flights or surveyor visits, the operational benefit is decisive: no downtime, no no-fly windows, no weather dependency. Instead, a timestamped 3D block model after every scan cycle — the basis for FIFO tracking, dead-inventory detection and a clean material-balance reconciliation between intake, storage and dispatch. OWL EYE® STOCKPILE implements this principle in storage buildings and outdoor yards: fixed 3D-LiDAR sensors mounted on the roof, light masts or building structure, a single dashboard for logistics, sales and reporting. Architecture and reference customers under Stockpile monitoring; full portfolio under Solutions.
What is stockpile measurement? ＋
Stockpile measurement is the process of capturing the volume — and from it the tonnage — of a stockpile, i.e. a heap of bulk material such as ore, coal, aggregates, salt, grain or wood chips. The result is a number (cubic metres, tonnes) that feeds inventory, FIFO tracking, material balance and statutory reporting. Four methods dominate in industry: manual tape-and-rod surveying (slow, requires shutdown, ±2-3%), drone aerial photogrammetry (fast for open yards, 1–3% with ground control and 3–5% without, weather-bound, no indoor coverage), terrestrial laser scanning (survey-grade, <1%, but periodic — one-off audits), and fixed LiDAR mounted on roofs or masts (±1%, continuous 24/7, indoor and outdoor). OWL EYE® STOCKPILE is the fixed-LiDAR approach: permanently installed 3D-LiDAR sensors deliver real-time stockpile measurement with ±1% accuracy. Each scan is archived as a 3D block model, enabling FIFO tracking, dead-inventory elimination, inventory reconciliation against weighbridge tickets, and shift-by-shift throughput reporting. For one-off survey-grade audits we also offer the terrestrial scan as the Bulk Inventory service.
Which bulk materials does OWL EYE® STOCKPILE measure? ＋
Any solid bulk material with a defined surface — salt, potash, sugar, wood chips, pellets, biomass, coal, coke, limestone, gravel, ores, scrap, mineral concentrates, recyclate. The 3D-LiDAR captures surface geometry independent of colour or material composition; the volume-to-mass conversion is calibrated per material via a single density coefficient. Edge cases: extremely reflective materials (clean copper sheet, polished metal piles) or fully transparent ones — for those we add a complementary sensor type to the installation.
What hardware does a LiDAR stockpile measurement system use? ＋
A fixed LiDAR stockpile measurement system uses several 3D-LiDAR sensors — for example Livox Avia or Mid-360; sensors from other manufacturers such as Hesai or Pepperl+Fuchs can be combined in the same installation. They sit in stainless-steel mounts with weather hoods (protection class IP65+, −40 to +80 °C, optional compressed-air cleaning against dust) on roofs, light masts, power poles or the building structure, and connect via WLAN, LTE, Ethernet or fibre. The sensors we supply: Livox & Hesai LiDAR sensors. LiDAR stockpile measurement works on the Time-of-Flight principle. Each sensor emits short laser pulses and times the reflection back from the pile surface. From millions of pulses per second, the sensor reconstructs a dense 3D point cloud of the heap — distance and angle for every point. A fixed installation uses multiple sensors mounted overhead — on the building roof, on masts, on the gantry of a stacker-reclaimer — with overlapping cones so the entire pile is covered without shadow zones. The software pipeline then turns the point cloud into a closed surface mesh, computes the volume against a stored reference floor, and applies a calibrated bulk-density value to derive tonnage. Polygons drawn in the dashboard separate volumes by bay, grade or customer. LiDAR is contactless, runs 24/7 in any light, and works through dust thanks to multi-echo signal processing — the sensor evaluates first and last return separately, ignoring airborne dust echoes and locking onto the solid pile surface. See OWL EYE® STOCKPILE for the production system, and /why-lidar/ for the technology rationale vs radar, ultrasonic and weighbridge approaches.
How accurate is stockpile volume measurement with LiDAR? ＋
Stockpile volume measurement with stationary 3D-LiDAR sensors reaches a volumetric accuracy of ±1 % in a calibrated installation. The figure is from production operations — K+S (salt piles in open storage), Nordzucker (sugar-syrup piles and beet bunkers), proFagus (wood piles in outdoor yards), Aurubis (concentrate piles) and Sachtleben Minerals — and not a laboratory claim. Residual uncertainty stems mostly from material density, not from the geometric capture: LiDAR measures volume directly; converting to tonnage depends on moisture, grain size and storage compaction. Method comparison: drone photogrammetry delivers 1–3 % on volume with a surveyed ground-control network and 3–5 % without, depending on flight altitude, lighting and GCP layout. A terrestrial laser scan with a survey-grade Riegl VZ-1000 achieves <1 % as a single capture, but is not a continuous mode. Stationary multi-LiDAR systems sit at ±1 % and deliver the decisive advantage: every shift, every hour, no downtime, no pilot, no walk-around. OWL EYE® STOCKPILE installs the sensors on the roof, light masts or building structure as a turnkey solution; calibration is a one-off on-site step against a reference scan. Sensor architecture, references and integration under Stockpile volume measurement.
Which factors influence stockpile measurement accuracy? ＋
Fixed multi-sensor LiDAR delivers ±1% volumetric accuracy for stockpile measurement under industrial conditions, measured at active sites — not a lab figure. The number is reproducible across cement clinker domes, salt warehouses, ore piles, sugar silos and wood-chip yards. Three factors set the achievable accuracy: material-density calibration (the conversion from m³ to tonnes is only as good as the density model — we calibrate per material and per moisture band), sensor coverage and overlap (enough sensors with overlapping cones to eliminate shadow zones on the pile), and dust mitigation (multi-echo processing plus, where needed, software dust filters tuned per site). Get those three right and ±1% holds 24/7. In context: terrestrial survey-grade scanners reach >99% accuracy (<1% error) — better, but only for periodic one-off audits because they require an on-site operator. Drone photogrammetry lands at 1–3% with a surveyed ground-control network and 3–5% without and is weather-bound. Fixed LiDAR at ±1% continuous is the operational sweet spot. Reference deployments: K+S (salt), Nordzucker (sugar), proFagus (wood charcoal), Aurubis (copper concentrate), Sachtleben Minerals (barite). See /stockpile/ for the system and /why-lidar/ for the technology comparison.
How many sensors does my storage building need? ＋
It depends on pile geometry, bin layout and material shape. Concrete reference points from typical installations:
  • Storage bin 10 × 20 m: usually one sensor — and often a single sensor covers two adjacent bins.
  • Long storage bin 12 × 50 m: two sensors per bin. When multiple such bins sit side-by-side, two sensors typically cover two bins together.
  • Large storage building 100 × 100 m with multiple zones or piles: at least 6-12 sensors, depending on pile shapes, internal supports and sight lines.
Higher mounting positions cover more area per sensor. We calculate the optimal layout during the on-site survey before any quote, including blind-spot analysis — you only pay for the sensors you actually need.
How does OWL EYE® monitor ore stockpiles at steel and mining sites? ＋
Ore yards — iron ore, copper, bauxite, manganese, nickel concentrates — are continuous-flow environments where stacker, reclaimer and conveyor traffic never stops. Sending in a survey crew is unsafe, drone overflights only give a snapshot, and bunker-style level sensors miss the blending geometry. OWL EYE® delivers ore stockpile monitoring via permanently mounted 3D-LiDAR sensors on mast clusters or building structure. The point clouds fuse into one block model that is stacker- and reclaimer-aware: blending-bed ratios, per-zone inventory and FIFO aging are tracked automatically with ±1% volume accuracy. The dashboard plugs into burden-control, MES and ERP via REST, OPC UA and SAP — turning the ore yard from an estimate into a live tonnage figure.
How does OWL EYE® monitor aggregate stockpiles and material bays? ＋
Aggregate yards — sand, gravel, crushed rock, recycled aggregates, C&D fines — typically split into sectioned bays of differing grain size and grade. Manual surveys lag the daily turnover, weighbridge tickets only capture intake, and per-bay reconciliation is normally done by eye. OWL EYE® STOCKPILE delivers continuous aggregate stockpile monitoring from overhead 3D-LiDAR. A single sensor cluster covers multiple bays; polygons drawn in the dashboard separate volumes by bay, by grade, by customer reservation. Each scan updates per-bay inventory, intake/reclaim curves and aging — so dispatch, sales and statutory reporting work from the same live number. Throughput on transfer belts is captured by OWL EYE® VOLUME FLOW on the same platform.
How does OWL EYE® monitor waste and scrap stockpiles? ＋
Waste and scrap yards are the hardest case: heterogeneous material, rapidly changing geometry, varying bulk density, dust, and a regulatory obligation to report what actually sits on site. Weighbridge data alone hides waste inventory between intake and dispatch, and the bulk density a weight calculation depends on is essentially an estimate. OWL EYE® STOCKPILE delivers waste stockpile monitoring by capturing volume directly with permanently installed 3D-LiDAR — ±1% accuracy on the pile geometry itself, no density assumption required. Indoor scrap storage buildings, outdoor metal yards, RDF/SRF bunkers and C&D streams are all covered by the same platform. Aging zones flag long-standing waste inventory before it becomes a compliance or fire-load problem; per-zone volume reconciles offtake contracts and statutory reports.
How does OWL EYE® monitor clinker and concentrate stockpiles? ＋
Clinker stores and mineral-concentrate stockpiles share a tough profile: high-value material, abrasive dust, FIFO ageing that matters for quality, and downstream mills that expect a steady blend. Manual gauging is slow and unsafe; bin-level radars miss the per-zone geometry needed for blending. OWL EYE® STOCKPILE delivers concentrate stockpile monitoring via overhead 3D-LiDAR mounted on building structure or mast clusters — continuous coverage of clinker domes, concentrate buildings and longitudinal blending beds, ±1% volume accuracy through dust. Per-zone concentrate inventory, blending-bed ratios and stacker/reclaimer position feed mill-feed control and homogenisation logic. Every measurement is archived as a timestamped 3D block model, so material aging is queryable backwards in time.
What does real-time measurement actually mean in OWL EYE®? ＋
In OWL EYE® real-time measurement means the sensor, the edge processing unit and the dashboard refresh in a continuous loop — typically within seconds of a fresh scan, not minutes or shifts. Every variant runs the same loop:
  • Volume Flow — cross-section line scans integrated over belt speed, updated several times per second for live volume / mass flow.
  • Stockpile — overhead 3D-LiDAR cycles a full scan per minute or per shift (configurable), so the dashboard reflects each intake, reclaim or reshape within seconds of completion.
  • Truck Terminal — ~8 s drive-through scan, payload published before the truck reaches the exit.
  • Bunkers & Feeders — continuous fill-level sampling at sub-second cadence.
"Real time" in this context is the time from physical change to value-in-the-control-room, not just a display refresh. Throughput, fill level and threshold alarms reach your SCADA, SAP or Power BI in the same scan cycle — so an operator reacts to what is happening, not what happened an hour ago.
How does OWL EYE® integrate with SAP, OPC UA and Power BI? ＋
OWL EYE® ships with the same integration toolkit across every variant — Volume Flow, Stockpile, Truck Terminal, Bunkers & Feeders and Mobile Mapping. SAP integration uses native SAP ABAP connectors that book volume or mass events straight into the production module (MM, PP, QM), so tonnages, stock movements and material flows stay in sync with no middleware in between. For real-time process control we expose a documented OPC UA server and a REST API. Volume, mass flow, fill level and threshold alarms reach DCS, SCADA, PLC or MES within seconds of every scan. For legacy automation we add Modbus TCP and 4–20 mA on the same edge unit. For analytics, Power BI integration reads the same measurement dataset via REST or a SQL view — one real-time measurement source of truth across operations, ERP and BI. Every interface is documented and ships as part of the standard package; container-based deployment lets your IT team run OWL EYE® on premise, in the DMZ or in a private cloud.
How does OWL EYE® STOCKPILE cope with clinker dust in a cement plant? ＋
Clinker silos and pre-blending buildings are among the dustiest environments on site — fine particulate plus residual heat from the cooler exhaust will fog any optical sensor that is not built for it. The OWL EYE® BUNKER / STOCKPILE heads we deploy in cement plants are IP65-rated stainless-steel housings with an optical window that is purged on a schedule by a compressed-air pulse (typically every 30 minutes inside a clinker building). The 3D-LiDAR itself sees through airborne dust by averaging multiple returns per voxel — accuracy stays inside +/- 1 % of the bulk volume even during reclaim. For aggressive chloride atmospheres around the cooler we ship a corrosion-resistant variant. The system runs 24/7 without operator attendance.
How does OWL EYE® integrate with a cement mill control system? ＋
Each OWL EYE® head exposes its volume, tonnage and zone-aged inventory as OPC UA tags and as REST endpoints. In a cement plant the typical wiring is: 3D-LiDAR → on-site edge server → mill PLC (Siemens PCS 7, ABB 800xA or Rockwell) via OPC UA, plus a parallel feed to the plant historian (PI, Aspen IP.21). For the kiln feed and the cement mill the system delivers a live silo level per minute so the operator can balance pre-blending, raw mill and finish-mill draw without manual dips. ERP-side (SAP S/4HANA, IFS) we push end-of-shift tonnage as an iDoc or REST call against the material-document API. See silo overfill protection for the safety-rated variant.
What is the typical ROI for OWL EYE® in a cement plant? ＋
For an integrated cement works moving 1.5–3 Mt of clinker per year, the three biggest savings stack roughly as follows:
  • Dead inventory: reclaim-side LiDAR typically uncovers 3–6 % of pile volume that was unreachable or aged out — at €25–€35 per tonne of cement that recoverable stock is worth €150k–€400k once.
  • FIFO + quality: age-tracked zones cut out-of-spec clinker blending by 1–2 %, avoiding off-grade campaigns.
  • Weighbridge avoidance: internal transfers to the cement mill stop touching the legal-for-trade scale, freeing 30–60 minutes per shift.
Hardware payback in a typical cement-plant configuration is 9–18 months.
Can OWL EYE® measure stockpiles near a blast furnace or EAF? ＋
Yes — and it is one of the use cases we ship the most ruggedised housing for. Sinter feed, coke yards, lump-ore bins and EAF scrap bays all sit close to radiant heat from the furnace plus airborne iron-oxide dust. The standard IP65 stainless head tolerates ambient up to about 60 °C; for line-of-sight to glowing slag or near the tap-hole we add an active-cooled sleeve and a heat-shielded window. The 3D-LiDAR sees through coke and ore dust because we work at infrared wavelengths well above the visible-light scattering peak, and we average multiple returns per voxel. Volume accuracy stays inside +/- 1 % on a coke stockpile during full reclaim. The sensor runs 24/7 without operator intervention.
How does OWL EYE® feed data into the blast-furnace Level 2 system? ＋
In a steelworks the Level 2 process-automation layer (typically Primetals, SMS digital or in-house) wants a clean, timestamped tonnage signal per material per minute — sinter, coke, lump ore, additions. OWL EYE® delivers it via OPC UA straight into the L2 burden-distribution model, plus a parallel feed to the historian (PI, IBA-PDA) for long-term metallurgical analysis. For the BOF and EAF scrap yard the integration is wider: 3D-LiDAR → edge server → mill MES (PSI Metals, QuMES) over REST, so charge-mix optimisation works with measured rather than nominal scrap volumes. ERP buyback (SAP S/4HANA) closes the loop on raw-material reconciliation. The signal is continuous, in real time — no manual dip, no truck count, no monthly survey.
What ROI does OWL EYE® deliver in a steelworks? ＋
Steel mills usually justify the system on three lines:
  • Coke and ore dead inventory: typical reclaim-side discovery is 4–8 % of the pile that surveys had double-counted or that aged out behind the reclaim front. On a 200 kt coke yard at €280–€350 per tonne that is a one-off recovery of €2–€5 m on the books.
  • L2 burden accuracy: a tighter sinter-to-coke ratio cuts coke rate by 2–4 kg/tHM — at a 3 Mt/a furnace that pays the sensor cluster in well under one year.
  • Weighbridge avoidance: internal transfers between yard and stockhouse stop queuing at the legal-for-trade scale.
See weighbridge alternative for the full TCO model.
Can OWL EYE® measure heterogeneous recycling material with mixed densities? ＋
Yes — recyclate, scrap and mixed waste are typical OWL EYE® STOCKPILE targets. The 3D-LiDAR measures surface geometry, so the volume signal is independent of what is in the pile: shredded metal, mixed plastics, paper bales, RDF, glass cullet, e-waste fragments — all just surfaces above a known floor. The mass conversion is the part that is sensitive to material mix. We solve it in two ways: per zone-polygon density coefficient (one number per product), or — for very mixed feed — a rolling density calibration tied to the weighbridge feedback every 50 trucks. Operators see volume in real time, while tonnage smooths to within +/- 2 % on truly heterogeneous piles. The IR signal sees through airborne paper and plastic dust without issue.
How does OWL EYE® integrate with a recycling-plant SCADA? ＋
Sorting plants and material-recovery facilities typically run a SCADA on top of a Siemens S7-1500 or Beckhoff PLC backbone, with a Wonderware / AVEVA or Ignition HMI. OWL EYE® hooks in three ways at once:
  • OPC UA tags for live volume, tonnage and per-zone age — consumed by the SCADA for hopper levels, bunker fill alarms and feed-rate balancing into the shredder or optical sorter.
  • REST / MQTT for the MES (e.g. AMCS, RecyClass) — closing the loop on input vs output reconciliation per shift.
  • ERP iDoc / REST against SAP S/4HANA or the recycling-specific ERP (Enwis, RSAG) for end-of-day tonnage and value-locked inventory reports.
See silo overfill protection for the safety-rated bunker variant.
What is the ROI of OWL EYE® in a recycling plant? ＋
Recycling sites typically book three savings:
  • Dead inventory recovery: on a mixed-recyclate yard we routinely surface 5–10 % of pile volume that the previous manual survey had missed — at €40–€180 per tonne for sorted output that is a one-off €100k–€600k.
  • Weighbridge avoidance for internal moves: wheel-loader transfers between input bay and shredder feed stop touching the legal-for-trade scale, freeing 20–40 minutes per shift and removing a constant bottleneck.
  • Quality bonus on output: zoned age tracking enables strict FIFO on hard-to-store fractions (RDF, paper) and avoids quality downgrades.
Hardware payback in a mid-sized MRF lands at 10–18 months.
How does OWL EYE® handle salt caking and corrosive halide atmospheres? ＋
Salt storage buildings have two stubborn problems for any sensor: chloride-rich air corrodes ordinary stainless steel, and surface caking changes the bulk density over time. The OWL EYE® heads we ship to salt mines and de-icing depots use the corrosion-resistant housing variant — coated aluminium or hardened stainless with a sealed optical window, IP65 and a built-in heater plus dew-point control to suppress condensation that would otherwise drive chloride pitting. Caking does not fool the geometry measurement (the surface is still measured at +/- 1 %), but it shifts mass per cubic metre. The dashboard supports a per-zone density coefficient that operators can re-calibrate per storage building and per season. Sensors run 24/7 and need a 6-monthly sight check plus a yearly window clean.
How does OWL EYE® connect to a salt-yard ERP and dispatch system? ＋
De-icing salt and industrial-salt operations are dispatch-driven — peak winter mornings move thousands of tonnes against political contracts. OWL EYE® STOCKPILE plugs into that stack at two levels:
  • ERP: SAP S/4HANA, Microsoft Dynamics 365 or the yard-specific ERP (e.g. K+S internal, Compass dispatch) — REST or iDoc push of total stock, per-zone tonnage and value-locked monthly close.
  • Dispatch / TMS: live volume per storage building feeds the truck-loading planner so the dispatcher can pre-commit tonnage without a manual walk in the dark.
Inside the storage building, the system also runs as a weighbridge alternative for internal moves — keeping the legal-for-trade scale free for outbound trucks under contract.
What ROI does OWL EYE® deliver in a salt operation? ＋
Salt mines and de-icing-salt depots typically book three lines:
  • Dead inventory recovery: on a 100–250 kt road-salt hall we routinely surface 4–7 % of pile volume that manual surveys had double-counted between zones — at €60–€90 per tonne that is a one-off recovery of €240k–€1.5 m on the books.
  • Peak-day weighbridge avoidance: internal hall transfers stop queuing at the legal-for-trade scale, which is what bottlenecks the dispatch window on a snow morning.
  • Caking + FIFO: age-tracked zones cut the share of caked surface stock the loader has to break up.
Payback for a depot-scale install lands at 8–14 months.
Does grain moisture affect OWL EYE® STOCKPILE accuracy? ＋
The 3D-LiDAR measures the surface geometry of the grain pile, and that signal is unaffected by moisture content — wheat at 12 % and wheat at 16 % look identical to the sensor. Volume accuracy stays inside +/- 1 % regardless. Moisture affects the volume-to-mass conversion, because bulk density of grain changes by roughly 0.7–1.2 % per percentage point of moisture above the storage baseline. The dashboard handles this with a per-zone density coefficient that operators set per intake batch, or that we automate by reading the moisture probe at the elevator bucket and adjusting in real time. Net mass accuracy on a managed grain elevator typically lands inside +/- 1.5 %, which is well below normal weighbridge campaign variance.
How does OWL EYE® hook into a grain-elevator PLC and silo management system? ＋
Grain elevators usually run a Siemens S7 or Allen-Bradley PLC on the conveying lines plus a silo management system (e.g. Cimbria SMS, AgriLogic, Bühler MERCATOR) on top. OWL EYE® speaks the relevant protocols natively:
  • OPC UA for live silo and flat-store volume — consumed by the PLC for overfill protection and conveyor routing.
  • REST / Modbus TCP for the silo management system — per-bin tonnage, per-zone age, intake vs reclaim balance.
  • ERP push (SAP S/4HANA, Microsoft Dynamics, or grain-specific ERPs like Cultura, NextFarm) for monthly closing and customer-account inventory.
Combined with a silo overfill protection licence, the loop is closed both for accounting and for safety.
What ROI does OWL EYE® deliver in a grain elevator? ＋
Grain elevators and feed mills typically book three savings:
  • FIFO + spoilage: on a 50–100 kt flat store the age-tracked zones cut the share of grain that crosses the spoilage threshold by 0.5–1.5 % — at €200–€280 per tonne that is €100k–€400k per year in recovered first-quality output.
  • Dead corners: reclaim-side LiDAR surfaces 2–4 % of pile volume that the loader had stopped reaching — booked once into closing stock.
  • Weighbridge avoidance: internal transfers between flat store and silo stop touching the legal-for-trade scale.
Add the reduction in monthly manual surveys (no climbing, no laser tape, no spreadsheet) and payback in a mid-sized elevator lands at 10–16 months.
Can OWL EYE® handle the bulk-density variation of wood chips and biomass? ＋
Yes — and this is where stationary 3D-LiDAR clearly beats truck-counting or belt-scale-only operation. Wood chips, hog fuel, bark and pellet feedstock vary in bulk density between 250 and 450 kg/m³ depending on moisture, species mix and compaction. The 3D-LiDAR measures the surface geometry, so the volume signal stays accurate to +/- 1 % regardless of what the density is. The volume-to-mass conversion is handled per zone: operators set a density per product (debarked spruce, mixed hardwood, pellets) and per intake batch. For boiler-feed sites the system can read the moisture analyser at the belt and adjust the density in real time. End result: the boiler controller sees a clean continuous tonnage signal instead of a step function from the weighbridge ticket.
How does OWL EYE® integrate with a sawmill or biomass-plant control system? ＋
Sawmills and pellet plants typically run a Siemens, Beckhoff or Allen-Bradley PLC on the line, with a mill MES (e.g. MiCROTEC, USNR, LIGNUM) and an ERP (SAP S/4HANA, Microsoft Dynamics, branche-specific T-Wood / Profitree) on top. Biomass CHPs sit on a DCS like Siemens PCS 7 or ABB 800xA. OWL EYE® delivers volume, tonnage and per-zone age via:
  • OPC UA to the PLC / DCS for live boiler feed or sawmill log-yard balancing.
  • REST / MQTT to the MES for per-product inventory and end-of-shift reconciliation.
  • ERP push for monthly closing and customer-account reporting.
See silo overfill protection for the safety-rated pellet-silo variant.
What is the payback for OWL EYE® at a sawmill or biomass plant? ＋
Wood and biomass yards typically book three savings:
  • Dead inventory + density truth: a 30–80 kt wood-chip yard regularly reveals 5–9 % of pile volume that manual surveys had missed or that bulk-density assumptions had over/under-counted — at €40–€70 per tonne of dry chip that is €60k–€500k one-off.
  • Boiler feed stability: a continuous tonnage signal cuts boiler MW deviation by 1–3 %, reducing unplanned trips and fossil co-firing.
  • Weighbridge avoidance: internal moves between hog-fuel pad and silo stop touching the legal-for-trade scale.
In a typical biomass CHP setup, hardware payback lands at 10–18 months.
Is OWL EYE® safe in sugar silos with dust-explosion risk? ＋
Sugar dust is an explosive atmosphere (ATEX dust zones 20/21/22), and any sensor going into a sugar silo or a refined-sugar warehouse must carry the corresponding certification. OWL EYE® ships in an ATEX-rated variant for dust zones 20, 21 and 22, with the matching gas-zone option where solvents are present. The optical window is sealed at IP65, the housing is corrosion-resistant for sugar's hygroscopic chloride content, and a scheduled compressed-air pulse keeps the window clear. There are no moving parts inside the silo and no ignition source. Power and data leave the zone through certified barriers. The full ATEX detail is on the silo overfill protection page; that variant is also functional-safety rated for use in the overfill safety chain.
How does OWL EYE® plug into a sugar-refinery MES and ERP? ＋
Sugar refineries and beet-sugar factories run a Siemens PCS 7 or ABB 800xA DCS on the process side, a MES (e.g. PARSEC TrakSYS, AVEVA MES, Bühler MES) above it, and SAP S/4HANA on the ERP layer. OWL EYE® STOCKPILE and OWL EYE® BUNKER deliver continuous volume and tonnage data into all three:
  • OPC UA for live raw-sugar, refined-sugar and molasses silo levels — consumed by the DCS for overfill protection and crystalliser feed balancing.
  • REST to the MES for shift reconciliation and FIFO management of refined-sugar warehouses.
  • iDoc to SAP S/4HANA for material-document booking and monthly closing.
Combined with the ATEX-rated silo overfill protection licence, the same hardware also covers the safety chain.
What ROI does OWL EYE® deliver in a sugar refinery? ＋
Sugar producers typically justify OWL EYE® on three lines:
  • Refined-sugar FIFO: warehoused white sugar that ages out of bonus quality is the single biggest avoidable loss in the back end of a refinery. Age-tracked zone polygons cut quality downgrades by 0.5–1.5 % — at €450–€600 per tonne of premium output that is €200k–€900k per year on a medium refinery.
  • Raw-sugar dead inventory: reclaim-side LiDAR routinely uncovers 3–6 % of pile volume the manual survey had missed.
  • ATEX safety chain: replacing mechanical overfill switches with a measured continuous level removes a recurring inspection cost.
Hardware payback in a mid-sized refinery lands at 8–14 months.
What is a stockpile survey system (Haldenvermessungssystem)? ＋
A stockpile survey system — in German industry usage a Haldenvermessungssystem — is a permanently installed measurement setup that captures the volume and tonnage of bulk-material stockpiles automatically, without a surveyor walking the pile or a drone being flown. The core components are 3D sensors (LiDAR, in some products radar or cameras) mounted above the storage area, a processing unit that turns the point clouds into volumes, and a software layer that pushes the numbers into dashboards and ERP systems. The decisive difference to survey services is continuity: a service delivers one number per visit; a system delivers a number every scan cycle — hourly, per shift, or live. That turns stockpile surveying from an annual audit exercise into an operational data feed for FIFO, load-out planning and material balance. OWL EYE® STOCKPILE is such a system: fixed 3D-LiDAR sensors, ±1% volume accuracy, every scan archived as a 3D block model, delivered turn-key including mounting, calibration and SAP/OPC UA integration.
How does contactless stockpile surveying work in real time? ＋
Contactless stockpile surveying means no person and no device touches the pile: 3D-LiDAR sensors mounted on the roof, on light masts or on the building structure sweep the material surface with eye-safe laser pulses. Each sweep produces a point cloud of the entire pile geometry; overlapping sensor cones eliminate shadowed zones. The real-time part happens in software: every scan cycle is converted into volume (m³) and — via material-specific bulk density — into tonnage, then written to the dashboard and to interfaces such as REST, OPC UA or SAP within seconds. No downtime, no closed-off areas, no weather window: the measurement runs during normal loader and conveyor operation, indoors and outdoors, day and night. In production this means the difference between "last surveyed in March" and "current as of 14:03". OWL EYE® STOCKPILE delivers this contactless, real-time surveying at ±1% volume accuracy — proven at K+S, Nordzucker and proFagus, among others.
Stockpile surveying by drone vs. stationary LiDAR — what's the difference? ＋
Both produce a 3D model of the pile — the difference is frequency, coverage and recurring cost. A drone survey is a service: a pilot flies the yard, photogrammetry or airborne LiDAR turns the images into a model, and days later you receive a report. Accuracy with good ground control is 1–3%. It works well for large open yards measured monthly or quarterly — but it is weather- and daylight-bound, cannot fly inside buildings, and every additional flight costs again. A stationary LiDAR system is infrastructure: sensors are mounted once, then every scan is free. Volumes update continuously at ±1%, indoors and outdoors, and feed the ERP automatically. Cost per measurement is the wrong yardstick, though: the inventory is typically flown one to four times a year, and what a fixed system pays for is the time between surveys, when inventory discrepancies of 2–4% against book stock go unseen. Rule of thumb: if you need the number for the annual accounts, a drone survey does the job; if you need it for same-day decisions — reclaiming, blending, loading out, calling off a supplier — a fixed system does, with live FIFO and load-out data on top that no periodic survey can provide. Our own portfolio covers both sides honestly: drone survey as a service for periodic needs, OWL EYE® STOCKPILE for continuous surveying. Which fits your case is a 15-minute conversation, not a leap of faith — see also the full LiDAR vs. drone comparison.

Choosing a stockpile monitoring system

What is a stockpile measurement system? ＋
A stockpile measurement system determines the volume — and via bulk density the tonnage — of a pile of bulk material such as ore, coal, aggregates, salt, grain or wood chips. It is done with one of six system classes: stationary 3D-LiDAR (continuous, ±1 %), drone photogrammetry (1–3 % per flight with ground control), drone-borne LiDAR, mobile SLAM scanners, radar level sensors, or manual survey. The result feeds inventory accounting, production reconciliation and process control. Full comparison: stockpile monitoring systems compared.
What is the best stockpile monitoring system? ＋
It depends on the task, not the technology. For continuous 24/7 inventory and process control, stationary 3D-LiDAR is the strongest option (±1 % volume, works indoors, no personnel per measurement). For quarterly audits of large open yards, drone photogrammetry is more economical. For closed bunkers with permanent heavy dust, radar level sensors remain the pragmatic choice. All six system classes are set side by side in the stockpile monitoring systems comparison.
Which company makes the best LiDAR stockpile monitoring system? ＋
Several vendors build fixed-LiDAR stockpile systems. Meaningful selection criteria are: proven volumetric accuracy on real piles (ask for a reference measurement, not a datasheet), indoor capability, per-zone density calibration, and ERP/SCADA integration depth. OWL EYE® delivers ±1 % volume accuracy with per-zone density calibration and REST/OPC-UA integration — and because we also fly drone surveys and walk manual inventories ourselves, we will tell you honestly when a fixed system is not the right fit.
What is a stockpile management system? ＋
A stockpile management system combines continuous volume measurement with the operational layer on top: per-zone inventory and FIFO age tracking, reclaim guidance, reconciliation against weighed movements, and ERP/SCADA integration. Measurement tells you how much is on the yard; management turns that number into decisions. OWL EYE® STOCKPILE covers both layers — see stockpile measurement & monitoring and dead inventory & FIFO tracking.
How accurate is stockpile measurement? ＋
Typical volumetric accuracy by method: walking surveys and profile estimates deviate 5–15 % on irregular piles; drone photogrammetry with good ground control reaches 1–3 %; terrestrial laser scanning reaches sub-percent accuracy as a snapshot; stationary 3D-LiDAR reaches ±1 % continuously. Tonnage accuracy additionally depends on the density assumption — a fixed density factor can add several percent of error regardless of survey method.
Is a drone or fixed LiDAR better for stockpile inventory? ＋
Cadence decides. A drone gives you a snapshot per flight — ideal for monthly or quarterly stocktaking across large open areas. Fixed LiDAR measures every pile continuously, so book cut-off volumes, shift reports and reconciliation all read from live data. Many operations run both: LiDAR for the daily number, a drone for occasional as-built documentation. Detailed comparison: LiDAR vs drone.
Can stockpile volume be measured indoors or under a roof? ＋
Yes — with stationary LiDAR or a handheld SLAM scanner. Drones are generally not an option inside halls and domes (no GNSS, flight restrictions, dust). Ceiling- or truss-mounted 3D-LiDAR sensors measure indoor piles continuously, including flat storages, domes and waste bunkers.
What does continuous stockpile monitoring cost? ＋
A single silo or storage bay can be equipped for about €5,000–10,000; larger yards scale with sensor count and geometry — not with how often you measure. Systems are available as capex (purchase) or opex (subscription), plus a rental option for trials. That inverts the economics of per-flight or per-survey pricing: above roughly one measurement per month, continuous LiDAR usually becomes the cheaper option per measurement, and the 24/7 data feed comes free with it. Send us your yard layout for a concrete budget. Full cost breakdown with real numbers: what stockpile monitoring costs.
How often should stockpiles be measured? ＋
Match the frequency to the job the number does. If stock volumes only feed the year-end balance sheet, one audit-grade survey per year is enough. If they drive monthly reporting or purchasing decisions, a monthly drone or laser survey keeps book values inside a usable error band. Once stock figures steer daily operations — blending, loading, reconciliation against belt scales — snapshots arrive too late, and continuous monitoring with fixed LiDAR becomes the right tool: not because each measurement is cheaper, but because it delivers the daily stock figures a periodic survey cannot. The full decision logic is in our guide: how often should stockpiles be measured?

OWL EYE® Truck Terminal

What is a load volume scanner? ＋
A load volume scanner measures the volume of a truck load with laser/LiDAR — no contact — instead of weighing mass mechanically. With OWL EYE® TERMINAL, two LiDAR masts flank the lane; the truck drives through at up to 10 km/h while the system captures it as a dense 3D point cloud and computes volume, payload and load height plus a 3D model per vehicle in about 8 seconds. Compared with a weighbridge: no pit, no stopping, no civil works — and dimensions a scale never sees (load shape, overfill, off-centre loading, residual volume in partially emptied tippers). Use it as a weighbridge alternative or as a second source of truth alongside your certified scale. Details: OWL EYE® TERMINAL — drive-through truck volume measurement.
How does truck volume measurement with LiDAR work? ＋
Truck volume measurement with LiDAR works on the time-of-flight principle: sensors on two masts fire laser pulses at the passing load and reconstruct the surface profile from the reflections. OWL EYE® TERMINAL captures the vehicle as a dense 3D point cloud as it drives through at up to 10 km/h; the point cloud yields a 3D model of the load — volume to ±1 % accuracy, in about 8 seconds. For payload, the volume is converted via material-calibrated bulk density; empty reference scans per vehicle type also enable residual-volume measurement in partially emptied tippers. Results are handed to truck management, scale software or ERP in under 10 seconds. System page: OWL EYE® TERMINAL; cost comparison vs the scale: weighbridge alternative.
How does a truck volume scanner measure the load volume? ＋
A truck volume scanner measures the load by its geometry, not by its weight. With OWL EYE® TERMINAL, two LiDAR masts flank the lane and capture the truck as a dense 3D point cloud while it drives through at up to 10 km/h; a pass takes about 8 seconds. The software compares the loaded truck with a reference scan of the same vehicle empty: the space between the empty bed and the load surface is the load volume, measured to ±1 %. Multiplied by the bulk density of the material, the volume gives the payload in tonnes — truck load volume measurement and load height from a single pass. A truck load scanner complements the weighbridge: for legal-for-trade billing, the certified scale remains the reference.
Do trucks need to stop? ＋
No. OWL EYE® TERMINAL is a drive-through scanner: trucks pass through the dual-mast gantry at 0–10 km/h and the system captures each truck as a dense 3D point cloud while it drives through, processed into a complete 3D load model. Total time per truck is around 8 seconds — no stopping, no manoeuvring, no driver action. The scan itself needs no weighbridge — for legal-for-trade weighing you keep the certified scale. Volume, mass (density-calibrated) and load shape are delivered to your truck-management system before the vehicle reaches the exit.
How fast can the truck drive through the terminal? ＋
Up to 10 km/h drive-through speed — typical operations run at 5-8 km/h walking pace. The dual-mast LiDAR captures a full 3D snapshot in about 8 seconds. The truck does not stop, does not need to align precisely (a ±0.5 m lateral tolerance is fine), and does not need a driver action — the system triggers automatically on entry via inductive loop, light barrier or RFID.
How does the volume data integrate with our weighbridge / WAA / ERP? ＋
OWL EYE® TERMINAL ships with REST and OPC UA interfaces and a dedicated weighbridge sync mode that pairs each scan with the matching net-weight reading via vehicle ID, time stamp or RFID. From there the data flows into your WAA, SAP or any ERP — same payload as a manual weighing event, just enriched with volume, load height and a 3D image. Most terminals are live within one shift after the first commissioning day.
Can OWL EYE® TERMINAL replace a weighbridge for truck load control? ＋
Partly — it depends on what the figure is for. A weighbridge weighs the truck; calibrated and certified, it is the legal-for-trade instrument for billing and custody transfer. OWL EYE® TERMINAL measures the load volume (and, with material density, mass) as the truck drives through at up to 10 km/h — no stopping, no queue. For legal-for-trade weighing, keep the weighbridge. For load control — checking that trucks are not over- or under-loaded, reconciling deliveries, measuring throughput, capturing load shape and off-centre loading — drive-through volume measurement is the faster, queue-free option, and it sees things a scale cannot (the geometry of the load). Many sites run both: the weighbridge as the certified mass reference, OWL EYE® TERMINAL for fast load-control on every pass. If you only need load control and not fiscal weighing, a volumetric drive-through measurement can replace the weighbridge process entirely. Tell us your case at info@sachtleben-technology.com.
What does a truck volume measurement system cost? ＋
The OWL EYE® TERMINAL base configuration starts at approximately €25,000 plus an annual maintenance fee. The scanner gantry is simple steelwork — built by your local contractor to our drawings, or we organise the complete installation. Vehicle identification via number plate recognition (ANPR) or RFID is available as an option. Send us your gate layout for a firm quote.
What is drive-through truck scanning and how fast is it? ＋
Drive-through truck scanning captures the volume, height and shape of a truck's load with 3D-LiDAR while the vehicle passes through a gantry — no stop, no manoeuvring, no driver action. With OWL EYE® TERMINAL two LiDAR masts flank the truck lane and capture the vehicle as a dense 3D point cloud as it drives through, which the edge unit turns into a complete 3D load model. Trucks drive through at 0–10 km/h (typical operation is 5–8 km/h, walking pace). End-to-end the system delivers volume in m³, mass in tonnes (density-calibrated) and a per-truck 3D snapshot to your truck-management system in roughly 8 seconds per truck. Compared to a weighbridge, a drive-through truck volume scanner removes the queue and adds load shape — useful for over- / under-load checks, supplier reconciliation and off-centre loading alerts. For legal-for-trade billing you keep the certified weighbridge; for everything else, the scan is the faster instrument.
How many more trucks per hour can OWL EYE® TERMINAL handle vs a weighbridge? ＋
In practice 2 to 4× the throughput of a stop-and-weigh process, depending on layout. A weighbridge typically processes 30 to 60 trucks per hour — each truck has to stop on the bridge, the driver has to wait for the ticket, and the queue builds at the entrance during peak hours. OWL EYE® TERMINAL measures the load volume as the truck drives through at up to 10 km/h: no stopping, no queue, no driver interaction. Realistic throughput sits at 120 to 200 trucks per hour on a single drive-through lane. The throughput gain only translates to a real operational benefit if the rest of your terminal (gate-in, gate-out, ERP booking) can keep up — we model that for you. For sites where the weighbridge is the bottleneck on peak shipping days, a drive-through volume lane often removes a queue that costs more in driver demurrage than the sensor itself. Tell us your peak-hour truck count at info@sachtleben-technology.com.
Can LiDAR truck scanning replace a weighbridge? ＋
For dispatch, reconciliation, load-shape control and per-truck volume — yes. The OWL EYE® Truck Terminal gantry runs at ±1 % volume accuracy and ±2–3 % mass after a one-off material density calibration, which covers the vast majority of operational use cases at higher throughput than a weighbridge. For legal-for-trade billing (MID / OIML certification) a weighbridge stays the reference instrument — LiDAR is not certified for custody transfer. The practical pattern at multi-material sites is to keep one calibrated weighbridge for invoicing and run a LiDAR gantry for everything operational: dispatch, queue management, under-/over-fill flagging and per-material reconciliation. The full positioning argument is on the weighbridge alternative page.
What is the accuracy of LiDAR vs a weighbridge? ＋
A modern certified weighbridge sits at 0.1–0.5 % mass after legal-for-trade calibration. OWL EYE® Truck Terminal LiDAR delivers ±1 % volume directly from the 3D scan and ±2–3 % mass after a one-off per-material density calibration. The accuracy difference matters at the level of a single fiscal invoice — it does not matter at the level of dispatch decisions, daily material balance or under-/over-fill control, where ±2–3 % is far inside the practical tolerance bulk operations already accept (loading variation between trucks is typically larger than this). The detailed side-by-side data table is on the LiDAR vs weighbridge page.
How much does a weighbridge cost vs an OWL EYE® gantry? ＋
A 60-tonne legal-for-trade truck weighbridge — pit, civil works, load cells, software, gate hardware — typically lands in the €120k–€180k range before site preparation. Recurring annual cost: legal recalibration, load-cell replacement, pit drainage. An OWL EYE® Truck Terminal gantry — two synchronised 3D-LiDAR heads, gantry steel, dashboard licence, commissioning — typically sits in the €30k–€50k envelope for a complete project including commissioning; base configurations start at approx. €25,000. No pit, no load-cell replacement, no annual legal-for-trade recalibration. Recurring cost is one yearly window service and the software subscription. Where the comparison decisively flips is on civil works: a new weighbridge pit alone can run €30k–€60k, and the prepared LiDAR surface is closer to €5k. For the full TCO break-down see the weighbridge alternative page.

OWL EYE® Volume Flow

What is volume flow measurement on a conveyor belt? ＋
Volume flow measurement is the continuous capture of the material stream on a moving conveyor belt — as volume per time (m³/h) instead of weighed mass. A 2D-LiDAR sensor above the belt scans the bulk material's cross-section profile line by line; from profile and belt speed the system computes the volume flow in real time, to ±1 % accuracy. Mass flow is derived via material-calibrated bulk density. The difference from a belt scale: no moving parts, no wear, no recalibration after a belt change — plus belt load, height profile and mistracking detection that a scale never delivers. Multi-echo signal processing separates airborne dust from the material profile. Details: OWL EYE® VOLUME FLOW — conveyor volume flow measurement; the head-to-head comparison: LiDAR vs belt scale.
How do you measure the volume flow on a conveyor belt — belt scale, radiometric gauge, radar or LiDAR? ＋
The material flow on a conveyor belt is measured either by mass or by volume. A belt scale weighs the material through idlers on load cells: 0.5–1 % mass accuracy when calibrated, with mechanical wear and periodic recalibration. A radiometric (nuclear) gauge infers belt load from the attenuation of a radioactive source: non-contact, but with licensing, shielding and source-disposal costs. Microwave or radar sensors give a point load signal without a cross-section profile. Volumetric LiDAR scans the material cross-section line by line and, with belt speed, computes the volume flow (m³/h) and — with density — the mass flow (t/h): ±1 %, non-contact, no wear, load profile included. In practice the belt scale remains the reference for custody-transfer weight; for process control, retrofits without rebuilding the belt and multi-belt monitoring, OWL EYE® VOLUME FLOW is the non-contact conveyor volume flow measurement. All seven methods on the belt compared: conveyor belt volume flow measurement: 7 methods compared; for stockpiles and bunkers: six ways to measure bulk volume.
What is volumetric conveyor belt measurement? ＋
Volumetric conveyor belt measurement is the contactless capture of the cross-section of material moving on a conveyor belt — converted in real time into volume flow (m³/h) and, with material density, into mass flow (t/h). Unlike a belt scale, which weighs the load through the belt frame, a volumetric system measures the actual geometric profile of the bulk material above the belt. OWL EYE® VOLUME FLOW performs volumetric conveyor belt measurement with a single 2D-LiDAR sensor mounted 0.5 to 1.5 m above the belt. The sensor scans line by line, crosswise to the belt direction. Each scan becomes a profile cross-section; integrated over belt speed, it delivers continuous, wear-free volume and mass-flow data — accurate to ±1 %, available 24/7 via dashboard, REST API and OPC UA. Typical use cases: replacing or supplementing belt scales on abrasive or wet materials, monitoring throughput on long conveyor lines, feeding live mass-flow data into SCADA / SAP / MES systems, and detecting off-centre loading or belt-edge spillage before it becomes a problem.
What is an optical belt scale — and how accurate is it compared with a mechanical belt scale? ＋
An optical belt scale measures the material flow on a conveyor without contact: a laser or LiDAR sensor above the belt captures the cross-section of the belt load; cross-section and belt speed give the volume flow in m³/h, and the calibrated bulk density turns it into mass flow in t/h. It does not weigh — it computes from geometry — so there are no load cells, no wear and no intervention in the belt line during installation. A mechanical (gravimetric) belt scale, by contrast, weighs with load cells under the belt: it is certifiable and remains the reference for custody transfer (below 0.25 %), but drifts by a typical 2–3 % between calibrations. OWL EYE® VOLUME FLOW is a LiDAR-based optical belt scale with ±1 % volume accuracy and no drift, which also delivers the load profile, off-centre loading and edge spillage. Head-to-head: belt scale vs. volumetric measurement.
How do you calculate mass flow in t/h from the measured conveyor volume flow? ＋
Mass flow (t/h) = volume flow (m³/h) × bulk density (t/m³). The LiDAR cross-section multiplied by belt speed gives the volume flow; bulk density is the material-specific factor. Example: a belt carrying 250 m³/h of crushed limestone at 1.5 t/m³ moves 375 t/h. With OWL EYE® VOLUME FLOW the bulk density is calibrated per material at commissioning — against a reference weighing (existing belt scale, weighbridge or sample weighing) — and stored as a material profile; moisture or grain-size changes get their own profile. The result is live volume and mass flow in m³/h and t/h at ±1 % volume accuracy, via dashboard, REST or OPC UA into your control system or ERP. The volume is always the primary measurement; the tonnage is only as good as the calibrated density. Basics: conveyor volume flow measurement; when the belt scale still stays: belt scale vs. volumetric measurement.
Which conveyor types and material flows are supported? ＋
OWL EYE® VOLUME FLOW works on standard troughed and flat belts, regardless of band width or material — typical installations cover 600 mm to 2200 mm wide belts running at 0.5 to 6 m/s. Bulk densities from light wood chips (~200 kg/m³) to dense iron ore (~4000 kg/m³) are calibrated material-by-material on commissioning. The 2D-LiDAR cross-scan does not touch the belt or the material, so abrasive, sticky, hot or wet bulk materials are no problem. Inclined and reversible belts are supported.
When is volumetric LiDAR the right choice over a traditional belt scale? ＋
Choose volumetric LiDAR (OWL EYE® VOLUME FLOW) over a belt scale when one or more of these apply:
  • Abrasive, sticky, hot or wet materials — a belt scale wears out fast or de-calibrates; a contactless LiDAR sensor mounted above the belt never touches the load and has no mechanical wear parts.
  • Retrofit on an existing conveyor — installing a belt scale means working in the belt line: a weighing frame takes the place of existing idler stations, the belt has to stand still for it, and alignment and calibration with test weights follow. A LiDAR sensor goes on a small gantry above the belt in hours, no belt stop required after the brief mounting.
  • You need profile data, not just total mass — LiDAR sees off-centre loading, belt-edge spillage, profile-height anomalies and can flag predictive-maintenance triggers. A belt scale reports only the integrated mass.
  • Multiple belts at one site — one LiDAR per belt is significantly cheaper than rebuilding multiple belt frames, and all data flows into one OWL EYE® dashboard with one set of APIs.
  • Material density varies — LiDAR measures geometry first; mass is derived per material calibration. A belt scale measures mass but cannot tell you the volume, which is what matters for stockpile-input reconciliation.
Stick with a belt scale when you have a single, well-calibrated, high-throughput belt with a uniform material and you need fiscal-grade weight accuracy (custody transfer at <0.25 %). For nearly every other industrial conveyor scenario, volumetric LiDAR is faster to install, cheaper to maintain, and gives you data the scale cannot. Many of our customers run both: belt scale for periodic re-calibration of the LiDAR mass output, LiDAR for continuous monitoring and the extra geometric data the scale cannot provide.
Is there an alternative to a belt scale — and how accurate is belt weighing compared with LiDAR? ＋
The alternative is the optical belt scale — volumetric conveyor measurement by LiDAR. A 2D-LiDAR sensor above the belt scans the material cross-section line by line; with belt speed this gives the volume flow (m³/h) and, via calibrated bulk density, the mass flow (t/h) — plus the load profile a scale never sees. No contact, no load cells, no wear, no intervention in the belt line. On accuracy: belt weighing reaches 0.5–1 % of mass on a well-calibrated belt and 0.25 % on certified custody-transfer scales — but it drifts with material build-up, idler wear and belt tension and needs periodic recalibration. LiDAR measures ±1 % by volume after a one-off reference calibration and does not drift; its mass figure follows density stability (±1–2 % for homogeneous bulk, ±3–5 % for variable mixes). For fiscal invoicing the belt scale remains the reference; for process control, retrofits and multi-belt sites OWL EYE® VOLUME FLOW is the alternative — full comparison: belt scale alternative.
What accuracy can OWL EYE® VOLUME FLOW achieve? ＋
Volume accuracy is typically ±1% on a calibrated belt. Mass output (tonnes per hour) follows from volume × material density, so mass accuracy depends on how stable the bulk density is — for homogeneous materials (sugar, salt, sand) typically ±1-2%, for variable materials (mixed scrap, recyclate) ±3-5%. We perform a one-off density calibration on commissioning and the system continuously cross-checks against weighbridge data if you have one — drift below 0.2%/year in normal operation.
How do you measure bulk material on a conveyor belt? ＋
Bulk material on a conveyor belt is measured by mounting a 2D-LiDAR across the belt and capturing thousands of cross-section lines per second. From each cross-section — profile shape, height, width — and the known belt speed, the system computes volumetric flow in m³/h. With a calibrated material density, the mass flow in t/h falls out in the same step. The method is contactless, has no mechanical wear and requires no work in the belt line. Compared to a belt scale, the practical advantages are clear: no belt stop for installation, no calibration marathon with reference weights, no load-cell re-trim after every belt change. The scan additionally delivers a full loading profile — off-centre loading, belt-edge spillage, belt mistracking and clumping are detected as flagged events long before they cause damage. A belt scale gives one number; a LiDAR belt scan gives throughput and conveyor-diagnostic data from a single sensor. In the OWL EYE® portfolio this is handled by VOLUME FLOW. Reference customers include K+S (salt belts), Nordzucker (sugar-beet intake) and proFagus (wood chips). The full comparison to traditional belt scales is at Why LiDAR.
What does installation on an existing conveyor look like? ＋
The 2D-LiDAR cross-scan unit is mounted on a small bracket above the belt — typically 1.5 to 4 m above the material. Mounting takes a few hours per belt and does not require belt downtime if structural side access exists. Wiring is power + Ethernet to the local control cabinet. Total commissioning time including material calibration is typically one shift per belt. We deliver the bracket pre-fabricated to your belt geometry — no on-site welding required.
How does the data reach our SCADA / SAP / MES system? ＋
Three standard interfaces ship out of the box: REST API (JSON over HTTPS), OPC UA server (industry standard for SCADA / PLC), and SAP IDoc connector for ERP. Volume, mass, throughput per minute / hour / shift, alarms — all available in real time. The dashboard runs in your browser; the raw data lives on our edge server inside your network. No cloud dependency required, no outbound internet connection needed for the production loop.
How is OWL EYE® belt scanning different from a belt scale? ＋
A belt scale integrates mass through load cells in the conveyor frame — one number, the total throughput. OWL EYE® belt scanning is a 2D-LiDAR cross-scan above the belt that captures the full load profile every line: shape, height, distribution, edges. That difference is decisive. A belt scale tells you how much; a belt scan also tells you how it sits — off-centre loading, profile asymmetry, belt-edge spillage, belt mistracking, chute wear. Volume (m³/h) and density-calibrated mass (t/h) come out as a side benefit of the scan. So: a belt scale weighs. A belt scan gives you flow data and conveyor diagnostics from one contactless sensor — no intervention in the belt line, no frame rebuild, no recalibration cycle. For nearly every retrofit on an existing conveyor, belt scanning installs faster, wears less and delivers more.
What load-profile anomalies can OWL EYE® detect on a conveyor belt? ＋
OWL EYE® captures a full cross-section of the load every scan line, so any deviation from the expected profile becomes a flaggable event. In practice the system detects:
  • Off-centre loading — the load centre of mass shifts left or right of the belt centreline, a typical sign of a worn or mis-adjusted chute.
  • Profile-height anomalies — sudden spikes, dips or hollows that indicate clumping, bridging upstream, or a feeder problem.
  • Belt-edge spillage — material climbing or overflowing the belt edge, captured continuously instead of only after a housekeeping round.
  • Belt mistracking — the entire profile drifts laterally over many minutes, the earliest visible sign of idler or roller trouble.
  • Asymmetric profile shape — the load profile slopes consistently to one side, a tell of skirt-board leaks or worn chute liners.
Each anomaly is configurable: threshold, persistence, hysteresis. Events route into your CMMS, OPC UA, dashboard or e-mail. The result is a conveyor belt load profile monitoring stream that powers preventative maintenance instead of waiting for failure.
How does a 3D belt scan feed preventative maintenance? ＋
A 3D belt scan turns a conveyor into a continuous condition source — and continuous condition data is exactly what a preventative-maintenance programme needs. OWL EYE® streams three classes of signal into your maintenance system:
  • Instant anomaly events — off-centre loading, spillage, profile spikes. Each event is timestamped and routed to your CMMS or OPC UA contact for an interlock or work order.
  • Slow-drift trends — gradual lateral profile drift indicates belt mistracking; gradual asymmetry indicates chute or skirt wear. The trend appears days or weeks before a visible failure.
  • Throughput-vs-profile baselines — for a given material and feed rate the profile shape is repeatable. Deviations from baseline correlate with chute wear, feeder issues and bunker discharge problems.
Combine those streams with your maintenance plan and conveyor stops shift from reactive to condition-based: the work order is generated before the breakdown, not after. That is preventative maintenance built on data the belt scale, switch and walk-down can never deliver.

Waste Bunker Monitoring

How does waste bunker monitoring with LiDAR work? ＋
Waste bunker monitoring with LiDAR uses 3D sensors on the bunker ceiling that scan the entire reception pit continuously. Unlike classic point-level measurement, LiDAR bunker monitoring delivers full-surface level measurement across the whole bunker: volume per sector, zone age (FIFO), live grab position and extraction per shift — in waste-to-energy plants, RDF power plants, biomass plants and coal-fired stations. Important context: LiDAR bunker monitoring does not replace fire-protection thermography — it complements it. The infrared camera spots hotspots; the LiDAR system knows volume, material movement and crane tracking. Together they form the complete picture of the bunker. Details: waste & fuel bunker monitoring.
Does bunker monitoring also work with biomass, coal and sewage sludge? ＋
Yes — the same LiDAR sensors that measure a WtE waste bunker work in biomass power plants (wood-chip bunkers), coal bunkers and sewage sludge reception bunkers. The sensor captures surface geometry regardless of material; conversion to tonnes uses a material-calibrated bulk density — including moisture bands for wood chips and dry-solids calibration for sludge. In biomass and sludge plants, fuel stock is measured in boiler-hours: the system delivers remaining runtime per bunker, crane tracking and cut-and-fill per shift — the same signals as in waste incineration. Dusty coal bunkers get the compressed-air window purge; ATEX areas get the Zone-22 housing variant. Details: waste & fuel bunker monitoring; for open yards see stockpile monitoring.
What does crane tracking in a waste bunker show? ＋
Crane tracking answers the three questions every control room asks: Where is the crane right now? How much did it take from where — and where did it put it? And is the bunker properly mixed? The live position of the waste-crane grab comes from the crane PLC or directly from the LiDAR scan; every grab move is linked to the volume diff of the affected sector — taken, dropped, restacked, per cycle. The movement picture answers the mixing question: sectors untouched for too long stand out immediately (FIFO indicator), and the mixing strategy for calorific-value homogenisation becomes verifiable — per shift, audit-proof in the log. Details: waste bunker monitoring & crane tracking.
What is a waste bunker — and why is it monitored? ＋
The waste bunker is the reception and storage pit of a waste-to-energy plant: a deep concrete pit into which collection trucks tip the waste, and from which a crane grab feeds the boiler. It buffers fluctuating deliveries against the continuous fuel demand of the incineration lines — while the crane operator mixes fresh and old, wet and dry fractions to keep the calorific value stable. Waste bunkers are monitored for two reasons: safety (fire detection by thermography, fill-level limits) and operations — volume per sector, age per zone, crane tracking and mixing quality. LiDAR monitoring delivers the second part: waste bunker monitoring with OWL EYE® — the 3D volume picture that thermography cannot see.
How does LiDAR cope with dust, methane and condensation in a waste bunker? ＋
Waste bunkers in WtE plants are dusty, humid and contain residual landfill gases — none of which defeat a properly specified 3D-LiDAR. OWL EYE® uses 905 nm pulsed time-of-flight with multi-echo processing: dust particles return weak first echoes, the bunker floor or heap returns the strong last echo, and the firmware selects the surface return automatically. Methane and water vapour are transparent at 905 nm, so combustible gas accumulations do not block the beam. The sensor head is housed in an IP65+ enclosure with an optional compressed-air purge ring around the optical window — typical cadence 30 minutes — plus an internal heater and dew-point control to suppress condensation on cold mornings. Optical filtering rejects ambient hall light and tipping-bay floodlights.
How does crane grab position synchronise with the LiDAR bunker scan? ＋
Two integration paths are supported, and both feed the same dashboard with per-grab volume estimates. Preferred: read grab position from the crane PLC over OPC UA or Profinet. We ship bridges for Liebherr, Demag and Kone control systems — XY, hoist height and grab open/close state stream into OWL EYE® at PLC cycle rate, and each grab cycle is correlated with the bunker delta of that sector. Fallback: pure LiDAR tracking. If the PLC is locked or the crane is third-party, the sensor identifies the grab as a moving rigid object above the heap surface, tracks its XY trajectory and infers the pick / drop events from velocity profile. Accuracy is lower than the PLC path but sufficient for sector-level FIFO and throughput accounting.
What is cut-and-fill in a waste bunker and how often is it computed? ＋
Cut-and-fill is a differential 3D analysis between two consecutive scans, broken down per bunker sector. The "cut" side records what was removed — typically the firing-line draw by the crane towards the feed hopper. The "fill" side records what was added — truck tipping bay or, in larger plants, a rail delivery. Default cadence is every 60 seconds in continuous mode, with a forced snapshot at shift change and at the start and end of each delivery vehicle event. Output per sector: tonnage drawn to the firing line, tonnage delivered, residual zones, and FIFO age in hours. The firing crew uses this to plan the mixture — fresh high-moisture intake gets blended with older, drier inventory to stabilise calorific value.
Is waste bunker LiDAR safe in dusty / ATEX zones? ＋
WtE waste bunkers are typically classified as ATEX zone 22 (combustible dust, rare and short-duration occurrence). OWL EYE® ships a zone-22-rated housing for these installations: enclosed optical window, no exposed sparking surfaces, surface temperature below the dust ignition class, and intrinsically-safe wiring on the power and signal sides. A heartbeat self-test runs continuously: the sensor reports its own optical health, internal temperature, window contamination level and last successful scan to the plant DCS, so a degraded sensor is flagged before it causes a measurement gap. Integration with the existing fire-protection system — CO sensors, IR heat detection in the bunker — is supported via a shared OPC UA tag set.