3 Types Of Tests Conducted in Weighing Scale Calibration

Just like any other measuring instrument, weighing scales also need to be calibrated regularly in order to ensure they give accurate readings. Over the time, for various reasons, the accuracy of balances and scales becomes less reliable. A proper weighing scale balance calibration service is the only way to know how accurate your weighing instruments are. Ignoring this important activity can turn measurement into guesswork. Here are 3 types of tests conducted in weighing scale calibration -


Weighing Test - The objective of weighing test is to test the accuracy of the weighing instrument throughout its range – in several steps, with increasing and decreasing weight. The most common practice is zeroing the instrument without any load. Loads of the first test point are set, and the tester waits for stabilization and records the results. The loads are then increased through all the increasing test points, and once the maximum load is indicated, the loads are decreased through the decreasing test points. In some cases, the weighing instrument may also be calibrated with increasing or decreasing loads only. Typically, 5 to 10 different test points are used. The highest test load is close to the maximum of the instrument and the smallest load is usually 10% of the maximum load. With multi-range instruments, each range is calibrated separately.


Eccentricity Test - In normal use, the load is not always placed perfectly at the center of the load receptor (the load’s center of gravity) of a weighing instrument. If the load is placed in different locations, the results can vary slightly. The eccentricity test is performed to check how much effect the location of the load has. In the test, firstly, the load is placed at the center of the load receptor and the result is observed. The reference load is then placed in different specified locations on the load receptor and results are observed to find out the difference caused by the varying location of the load. When there is a need to determine the errors of the indication, a calibrated load is used.


Repeatability Test - There are times when the same load is measured several times; the results are not always the same. Repeatability test is conducted to address this issue. The test is performed by replacing the same load on the same place on load receptor multiple times. Often, one load is used, however, several different load values can also be used separately. The instrument is first zeroed. The load is then placed on the load receptor and indication is recorded once it is stabilized. Then the load is removed and zero indication is checked and zeroed, in case necessary! Then the load is placed again, and so on.


When it comes to measuring sensitive data, even the smallest mistake in measurement can make a big difference. Whether you use robust industrial weighing scales or ultra-micro balances, choose Custom Calibration for reliable calibration services. Custom Calibration’s weighing scale calibration services are carried out in a controlled laboratory with NIST traceable standards to ensure consistent and accurate results.

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