Calibration vs. calibration
To clarify the difference between calibration and calibration, both terms must first be defined. It is crucial that the calibration, unlike the calibration, is a sovereign act. This means that verification is reserved solely for state institutions, usually the verification offices. The so-called manufacturer verification or initial verification by the manufacturer was replaced by the 2014/31 / EU directive through the conformity assessment. This means that every form of calibration is exclusively in the hands of the state. Nevertheless, many manufacturers stick to this name because it is known to those interested. Ultimately, the scope of the conformity assessment is identical to that of the verification and conformity-assessed scales according to Directive 2014/31 / EU may be used as well as verified scales in custody transfer.
When we speak of calibration, it is a representation of the deviation. The term is often confused with adjustment. In contrast to the adjustment, no change is made to the balance during calibration. The scale is loaded and unloaded in various ways according to the calibration instructions and the discrepancy is documented.
While error limits determine the further use of the balance during a calibration, the error during calibration does not play a role at first. If the balance is calibrated according to DAkkS, error limits must of course also be observed here. In the case of a factory calibration, it is up to the user whether he can continue to work with the detected error or not.
When a balance has to be calibrated is determined by Directive 2014/31 / EU, the Measurement and Verification Act and the Measurement and Verification Ordinance. In addition, other guidelines, laws and regulations can apply, e.g. if it is a scale for packaging food. The pre-packaging regulation also applies here. Basically, it can be assumed that a balance must always be verified if it is used to determine a weight that is used for billing. However, there are other applications where a calibrated scale must be used, such as Bathroom scales in hospitals. The calibration periods provide comprehensive information about the mandatory use of a verified scale.
If a scale is used exclusively for internal purposes, e.g. for quality assurance or picking, there is no need for calibration. This is particularly useful when the scale has to be very high-resolution. If particularly small and light parts are picked via a piece count, it makes no one to calibrate the counting system, especially since this is not possible anyway. The scale, i.e. the weight determination, can be calibrated, but not the piece counting. Scales that are used in such areas should be calibrated so that the user knows the tolerance of his scales and can react accordingly.
All quality assurance systems prescribe tested measuring equipment. DIN EN 9001: 2015 also requires regular testing of the measuring equipment. However, it is up to the user to what extent and at what intervals it is checked. A very sensible requirement, since the user can best estimate the importance of the measurement with the scales for the quality of his products.
Finally, it can be said that a calibrated scale must always be used when required by law and a calibrated scale is required as part of quality assurance.