Accuracy, resolution, and measurement error of scales
The accuracy of scales refers to their ability to display the correct measurement result of mass. It is crucial for precisely determining the weight of goods.
The resolution (or readability) of scales indicates the smallest mass value the device can detect. It depends on the design and the accuracy class of the instrument.
The measurement error of scales is the deviation between the measured and the true value. It can be positive or negative, depending on several factors such as operating conditions and calibration.
Classification of scales by accuracy class
Scales are classified according to their accuracy class, which defines their precision and the permissible measurement error. There are several accuracy classes:
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Special class (I) – highest accuracy, used in laboratories.
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High class (II) – for precise measurements.
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Medium class (III) – for general use in trade and industry.
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Ordinary class (IIII) – lowest accuracy, for household use.
Accuracy classes are regulated by standards and define the allowable measurement error for each class.
For example, medium-class scales are used in trade, where accuracy is important but not critical.
In Poland, the accuracy class of scales is governed by national metrological standards.
Verification of scales for measurement error
Verification (legalization) of scales for measurement error is a process of testing and calibrating scales to ensure their accuracy.
The stages of verification include:
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Visual inspection of the scale for damage.
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Checking the functionality of all components.
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Measuring mass using standard weights and comparing it with reference values.
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Adjusting the scale if necessary to eliminate errors.
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Issuing a certificate of conformity confirming compliance with established standards.
Verification of commercial scales is performed by accredited metrological organizations or authorized companies.
They ensure that the scales meet the required standards and legal regulations.
The process also involves checking the proper operation of the scales under working conditions — helping prevent measurement errors and maintain customer trust.
Permissible weighing error
The permissible weighing error depends on the accuracy class of the scale. Each class has defined tolerance limits:
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Special class (I) – minimal permissible error.
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High class (II) – slightly higher permissible error.
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Medium class (III) – higher permissible error than classes I and II.
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Ordinary class (IIII) – the highest permissible error.
The measurement error of scales, as defined by Polish and international standards, may vary.
The main goal is to ensure measurement accuracy according to the intended application of the scale.
Permissible errors are regulated by standards that guarantee reliability and precision of measurement results.
The measurement error is calculated by comparing the measured mass with the reference mass using the formula:
Measurement error = ((Measured mass – Reference mass) / Reference mass) × 100%
This allows users to determine whether the scale meets the required standards and is suitable for precise measurements.
Summary
Accuracy, resolution, and measurement error are key parameters for the reliable operation of scales.
Understanding these parameters and performing regular verification ensures measurement precision and compliance with metrological standards.
At VAGAR.PL, you can find high-quality precision scales of various types — including bench, beam, platform, retail, pallet, crane, and pallet truck scales with built-in weighing systems.
The right choice will not only ensure compliance with standards but also guarantee long-term reliability and stability of measurements.
