Kala Scale

Weighing Accuracy

Accuracy describes how close a measured value is to the true value or to an accepted reference standard. In weighing applications, accuracy is not only the number shown on the indicator. It is the result of the complete weighing system.

In daily operation, operators often trust a digital reading immediately because it looks clear and precise. However, every measurement has tolerance. A digital display improves readability, but it does not remove mechanical error, electrical noise, load cell drift, installation error, or calibration uncertainty.

A weighing result is reliable only when the load cell, mechanical structure, signal processing, calibration, and operating environment are all controlled correctly.

KALA’s technical advantage

KALA focuses on the complete weighing result, not only the load cell capacity. For truck scales, tank scales, hopper scales, silo weighing systems, batching systems, and automatic weighing lines, KALA evaluates the real application before selecting or replacing equipment.

The technical selection includes load distribution, required scale division, accuracy class, number of support points, mounting structure, cable distance, junction box type, moisture exposure, lightning protection, grounding, indicator compatibility, and long-term serviceability.

KALA works with proven load cell manufacturers such as CASC and CURIOTEC. CASC-made load cells are used in industrial weighing applications where strength, stability, and environmental protection are important. CURIOTEC, a Korean specialist in load and force sensors, provides strong options for truck scales, tank weighing, shear beam systems, compression weighing, and special measurement applications.

KALA’s value is the combination of reliable manufacturer technology and local engineering support: correct selection, correct installation, correct calibration, and fast troubleshooting.

Weighing equipment as a system

A weighing system includes many components: load cells, mounting accessories, junction boxes, cables, shielding, grounding, indicator or digitizer, mechanical frame, foundation, and calibration procedure. One weak component can limit the accuracy of the whole system.

In electronic weighing systems, the load cell is the core measuring transducer. It converts applied force into a proportional electrical signal. The indicator or digitizer processes that signal and displays the weight value.

A weighing system cannot deliver better accuracy than the load cells, installation quality, and calibration method allow.

The role of least count

The least count, also called resolution, is the smallest display step of a weighing instrument. For example, a 50,000 kg truck scale with 10 kg division displays weight in steps of 10 kg.

Resolution is related to readability. Accuracy is related to how close the displayed value is to the true weight. A scale with a smaller display division is not automatically a more accurate scale.

When KALA evaluates a weighing system, least count is checked together with load cell class, number of divisions, mechanical design, calibration condition, and legal metrology requirements.

Legal metrology perspective

Weighbridges, platform scales, bench scales, counter scales, and many industrial weighing instruments are classified as non-automatic weighing instruments. Depending on the application, they may need to comply with Vietnamese legal metrology requirements and applicable technical standards.

Scales used for trade, goods receiving, dispatch, invoicing, or taxation should be verified according to their accuracy class. In many common commercial and industrial applications, class III weighing instruments are widely used.

For trade-use scales, annual verification and proper calibration records are essential for reliable operation and legal compliance.

Accuracy classes for scales

For class I and class II instruments, the permissible error can be related to the least count by a factor such as 1, 2, 5, or 10 times the display division, depending on the instrument class and applicable standard.

For class III and class IV instruments, the practical tolerance is normally evaluated according to the relevant metrology rules, test load, and number of scale divisions. For many class III applications, accuracy is commonly considered around one scale division under verified operating conditions.

For example, a 50,000 kg x 10 kg truck scale must be supported by suitable load cells, correct installation, and proper calibration to achieve stable class III performance.

International standards

OIML is an important international reference for legal metrology. OIML R60 applies to load cells, while OIML R76 applies to non-automatic weighing instruments.

The relationship between load cell accuracy class and weighing instrument class is important when selecting load cells for a complete system.

In practical OIML compatibility checks, the certified number of load cell divisions should be equal to or higher than the weighing instrument divisions. The load cell accuracy class should also match the intended instrument class or be higher.

KALA checks this relationship before recommending CASC, CURIOTEC, or other compatible load cells for a weighing system.

Practical application

A 50 t truck scale with 10 kg division has 5,000 divisions. The selected load cells should therefore support at least 5,000 certified divisions, such as OIML C5 or a higher suitable class, depending on the full scale design.

A 60 kg platform scale with 20 g division has 3,000 divisions. In this case, a C3 load cell may be suitable if the mechanical structure, indicator, and calibration method also support the required performance.

In replacement projects, KALA also checks wiring, signal output, bridge resistance, mounting dimensions, sealing level, cable condition, junction box type, and indicator parameters. A load cell that fits mechanically may still be unsuitable electrically or metrologically.

The best weighing accuracy comes from selecting the correct load cell and controlling the complete system: structure, signal, calibration, environment, and service procedure.

Load cell accuracy classes

D1 to C2 load cells are suitable for simple weighing, construction material scales, non-trade applications, and systems where high precision is not required.

C3 is widely used in industrial weighing, including platform scales, belt scales, tank weighing, and many general-purpose electronic weighing systems.

C4 to C5 classes are used where higher accuracy is needed, such as truck scales, filling systems, checkweighers, and higher-performance industrial scales.

C6 load cells provide a very high level of accuracy for applications that require excellent stability, repeatability, and precision.

OIML R60 certification confirms that a load cell has been tested according to recognized metrological requirements and may be suitable for legal-for-trade weighing when used in a compatible system.

KALA support for CASC and CURIOTEC load cells

KALA supplies and supports load cells for truck scales, tank scales, hopper scales, silo weighing, crane scales, batching systems, and industrial automation lines.

With CASC-made load cells, KALA focuses on robust industrial applications requiring strong structure, stable output, suitable sealing, and reliable long-term performance.

With CURIOTEC load cells, KALA supports truck and tank weighing models such as NDSB and RPWB series, as well as other force measurement solutions where correct model selection and calibration are critical.

For new systems, upgrades, or replacement projects, KALA can help evaluate the complete weighing system and recommend the correct technical solution.

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kala@kalascale.com