Calibration

What You Should Know About Calibration

With the introduction of quality management standards all over the world, the requirements for measuring and test devices have become significantly more demanding. For example, the certification according to DIN EN ISO 9000+ requires an active quality management involving regular calibrations. With consideration of the specific environment this ensures a high reliability regarding the measuring results and the traceability of the measured values to the national standard.

“Calibration” is Not Identical with “Calibration by the Bureau of Standards”

Calibration includes those activities involved with determining, under given conditions, the relationship between the output values of an instrument or a measuring equipment and the corresponding values of a variable, which are determined by reference materials.

The Result of a Calibration

• The result of a calibration allows the evaluation of errors of dimension of the measuring instrument, measuring equipment or the setup of measuring instruments or the allocation of values to any scaled graduation marks.
• The result of a calibration can be fixed in a document, which is often called a ‘calibration report’ or a ‘calibration certificate’.
• In many cases, the result of a calibration is specified as correction or ‘calibration factor’ or as ‘calibration curve’.

“Calibration by the Bureau of Standards”

The expression Calibration by the Bureau of Standards is limited to the legal metrology and denotes governmental verifications, according to the calibration regulations. This type of calibration must only be performed by the Bureau of Standards responsible for the devices that are appropriate for verification

DKD Calibration

The calibration must only be performed within the range of those measurable variables, measuring ranges and measuring incertainties, which are specified in the PTB accreditation document. The customer receives a DKD calibration certificate specifying the measured values, the corresponding measuring incertainty, the designation of the calibration method, the environmental conditions and, as required, information on special measurement conditions. The calibrated object will be identified by a label (red).

The label contains the following data:

• Number of calibration
• Date of calibration (month/year)
• Number of the calibration laboratory and refers to the calibration certificate.

Note: DKD calibrations outside the range of accreditation services provided by the DKD calibration laboratory at Ahlborn Mess- und Regelungstechnik GmbH are performed by DKD laboratories run by our various partners.

AMR Factory Calibration

The calibration is performed according to comparison measurements with factory standards. Factory standards are (as far as possible) PTB or DKD calibrated measuring instruments, sensors or measuring systems. The customer receives a factory calibration certificate specifying the measured values, the corresponding measuring incertainty, the designation of the calibration method, the environmental conditions and, as required, information on special measurement conditions. The calibrated object will be identified by a label (green).

The label contains the following data:

• Number of calibration
• Company logo
• Date of calibration (month/year) and refers to the calibration certificate.

How Often to Calibrate?

The time interval between calibrations highly depends on the specific application and is influenced by the following parameters:

• Permissible measuring tolerances
• Environmental conditions
• Application frequency
• Results of previous calibrations
• Customer-specific requirements and definitions