How to Select Load Cells for an OIML-Compliant Truck Scale

A practical engineering guide for 80T weighbridges, OIML accuracy class, load cell capacity, and verification intervals.

For truck scales, an OIML-approved load cell is not the only factor that determines weighing accuracy, but it is an important foundation when the scale is used for trade, goods receiving, dispatch, invoicing, or legal metrology verification.

3x18m 80T 8 load cells x 30T OIML R60 C4/C6 d display division = 5kg verification scale interval (e) = 10kg/20kg

CURIOTEC NDSB-A 30T OIML C6/IP68 load cell for truck scales, heavy-duty weighbridges, tank scales, and industrial weighing systems.

I. What is the role of an OIML load cell in a truck scale?

OIML R60 is an international recommendation for evaluating load cells. A load cell with an OIML certificate has been tested for metrological performance such as combined error, repeatability, creep, temperature effect, and the certified number of load cell divisions.

However, an OIML certificate for the load cell does not automatically make the complete truck scale legal for trade. The scale also needs a suitable indicator, correct mechanical structure, proper installation, lightning protection, calibration with appropriate test weights, and verification according to local legal metrology requirements.

Short conclusion: for trade-use truck scales, it is recommended to use a load cell with a suitable OIML certificate. But real accuracy must still be controlled as a complete weighing system.

II. Practical example: 3x18m 80T truck scale with 5kg division

Assume a customer requires a 3x18m truck scale with 80T capacity and wants 5kg indication. Before selecting load cells, it is important to distinguish between d and e.

Symbol	Meaning	Practical role
d	Display division	The smallest step shown on the weighing indicator display.
e	Verification scale interval	The value used for accuracy class evaluation and legal metrology verification.

If 5kg is used as the verification scale interval (e), the number of scale intervals is:

n = Max / e = 80,000 / 5 = 16,000 scale intervals

This is a very high number for a truck scale. For a typical Class III weighing instrument under OIML R76, the commonly used maximum number of verification scale intervals is 10,000. Therefore, an 80T x 5kg truck scale should not be treated as a normal trade-use Class III configuration if 5kg is used as e.

KALA recommendation: use d = 5kg as a technical display division if the system is stable enough, but the verification scale interval (e) should be defined separately, commonly as 10kg or 20kg, depending on the equipment file, application, and legal verification requirement.

III. Recommended load cell configuration for a 3x18m 80T truck scale

For an 18m weighbridge, a stable and practical configuration is 8 load cells. This layout improves load distribution, reduces corner error, increases stability when trucks enter and leave the platform, and makes corner adjustment easier.

Item	KALA recommendation	Technical note
Weighbridge size	3 x 18m	Suitable for trucks, containers, tractor trailers, and heavy vehicles.
Scale capacity	80T	Dead load and axle load must also be considered.
Number of load cells	8 load cells	Stable layout for an 18m platform and easier corner adjustment.
Load cell capacity	30T/load cell	Good safety margin for dynamic load, eccentric load, and local overload.
Accuracy class	OIML R60 C5/C6 or a certified equivalent model	Recommended when e = 10kg or d = 5kg display is required.

IV. Why not select load cells by simply calculating 80T / 8?

If 80T is divided by 8 load cells, the average support load appears to be only about 10T per point. But this is not the correct way to select truck scale load cells, because real operating load also includes platform dead load, axle load, dynamic impact, eccentric loading, and local overload.

For this reason, for a 3x18m 80T truck scale, 8 load cells x 30T provides a more practical safety margin and better long-term reliability.

V. What should be checked in the load cell accuracy certificate?

Parameter	Meaning
OIML R60 class	Load cell accuracy class according to OIML R60.
n_LC / n_max	Maximum number of load cell divisions supported by the certificate.
v_min	Minimum load cell verification interval, important for multi-load-cell weighing systems.
Combined error	Combined effect of non-linearity, hysteresis, and repeatability.
Creep	Signal drift under constant load over time.

VI. CASC/South-Ocean and CURIOTEC in truck scale applications

CASC / South-Ocean has a technical background connected with China Aerospace Science and Technology Corporation. Its strength is precision mechanics, force measurement, load testing, error control, and signal stability in heavy industrial environments.

CURIOTEC is a Korean manufacturer specializing in load cells and force sensors. Product families such as NDSB/NDSB-A, CDSB, RPWB/RPWB-A, and digital versions are used in truck scales, tank weighing, silo weighing, and industrial force measurement systems.

Learn more about KDS 30tf / GF-1 OIML load cell .

VII. Conclusion for a 3x18m 80T truck scale

Question	Recommendation
How many load cells should be used?	8 load cells.
What capacity should each load cell have?	30T/load cell.
Which accuracy class should be selected?	Prefer OIML R60 C5/C6 or another certified model suitable for the complete scale design.
Is 80T x 5kg suitable?	It is suitable if 5kg is the d display division. If 5kg is the verification scale interval (e), n = 16,000 and the configuration should be treated as special.

VIII. Useful internal references

KALA supports load cell selection for CASC/South-Ocean, CURIOTEC, and other suitable load cell models for truck scales, tank scales, silo weighing, hopper scales, crane scales, and industrial weighing systems.

If you need to select load cells for a new truck scale, replace existing load cells, check OIML accuracy class, or evaluate the current scale configuration, contact KALA for technical support.

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Weighing Accuracy: Is OIML Required?