Five selection factors, five main load cell types, and the certifications that matter — a practical guide for engineers and buyers of industrial weighing systems.
1. Load Cell — The Heart of Every Weighing System
Load cells are the heart of any weighing system. Although often invisible because they are enclosed inside scales and machines, they are present in countless everyday operations: electronic scales, bottling and can-filling lines, drug-packaging machines, bagging and filling machines — plus applications across the automotive, logistics, aerospace, chemical and agri-food industries. Only quality load cells can ensure consistently accurate readings, thanks to reliable, repeatable strain gauges and properly treated materials.
2. How a Load Cell Works (Signal Stream)
Applied weight → body of steel/aluminum bends slightly → strain gauges change resistance → Wheatstone bridge outputs a signal → digital indicator processes the variation → weight is displayed
The strain gauges are high-precision electronic circuits, carefully placed inside the load cell body and protected from external damage. Because the deformation is tiny and the signal is small, the quality of the gauges, the bonding and the sealing determine whether the scale stays accurate after months of vibration, humidity and temperature changes.
3. Five Key Selection Factors
1. Environment. Temperature, humidity, corrosion and vibration all affect performance. Match the construction material (alloy steel, stainless steel) and IP rating to the installation environment.
2. Capacity. Define the load range so the cell is neither overloaded nor extremely underloaded. Prefer a capacity slightly higher than expected — it protects the system from unexpected overloads and load variations.
3. Precision & accuracy. Load cells vary in accuracy levels. If extremely precise measurements are required, select a model with high accuracy specifications (accuracy class, combined error, vmin).
4. Type of load. Different configurations measure tensile, compressive or shear forces. Make sure the load cell matches the force actually applied in your structure.
5. Approvals. If the measurement affects trade — weighing goods for sale or taxation — the application requires OIML R60 approved load cells (or the equivalent approval in your market).
4. Five Main Load Cell Types
Five common types of load cells
SINGLE POINT — ideal for weighing at every point on the platform; one load cell carries the whole platform. Typical: bench scales, floor platforms, fast checkweighing systems.
SHEAR BEAM — accurate weighing when force is applied at a specific point; robust and easy to mount. Typical: medium-capacity silos and hoppers, floor platforms.
BENDING BEAM — combines the responsiveness and accuracy of Single Point with the strength of Shear Beam. Typical: roller conveyors, floor platforms, silos, hoppers and small tanks.
TENSION / TRACTION — measures force exerted in tension; ideal for converting suspended vessels into weighing systems. Typical: suspended hoppers, hanging scales, suspended loads.
COMPRESSION — compact and robust, designed to weigh without mechanical bending; very durable under extreme stress. Typical: silos, hoppers and tanks of medium and large capacity, truck scales.
5. Certifications — What They Mean
Metrological approvals — for trade use OIML: international approval for equipment used in transactions with third parties. NTEP: the equivalent approval specific to the U.S. market.
Explosion hazard certifications — for dangerous environments ATEX: approval for equipment installed in explosive atmospheres (dust, gas, vapor). FM Approved: property loss prevention and safety equipment in commercial or industrial facilities. FM Approved cUS: equipment that also meets the requirements of the Standards Council of Canada.
6. Quick Selection Guide (KALA Recommendation)
Match the application first, then check the certificate
Bench scale, small platform → Single Point
Floor platform, medium silo/hopper → Shear Beam or Bending Beam
Suspended hopper or vessel → Tension / Traction
Large silo, tank, truck scale → Compression
Trade use (buying/selling, taxation) → any of the above, with OIML R60 approval
And remember: choose the load cell together with its mounting accessories (mounting kits, rocker pins, stay rods). A correct load cell installed with the wrong hardware will still produce corner errors and drift.
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KALA Technical Notes
This practical guide helps engineers and buyers select industrial load cells by environment, capacity, accuracy, load direction and certification. Always confirm the final choice against the manufacturer’s datasheet, official OIML certificate and applicable legal-metrology requirements. Need help matching a load cell to your platform, silo, tank or truck scale? Contact KALA technical support.
