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Calibration of Measuring Instruments

All CPT measuring equipment, such as electrical CPT conesmeasuring headsdata acquisition systems, and alike needs to be calibrated once in a while (see relevant standards). It helps customers achieve the highest measurement quality and productivity.

Calibration refers to the process of determining the relation between the output (or response) of a measuring instrument and the value of the input quantity or attribute, a measurement standard.

In non-specialized use, calibration is often regarded as including the process of adjusting the output or indication on a measurement instrument to agree with value of the applied standard, within a specified accuracy.

For a calibration to be of any value it must be accompanied by a traceable uncertainty statement (certificate) to an stated confidence level.

Gouda-Geo uses calibration data derived from one or more of the following sources: the Nederlands Meetinstituut (NMI) or other national laboratory (like NIST), a natural physical constant, or a ratio technique. The calibration reference data are on file at the NMI.

All calibrations are compliant with Gouda Geo-Equipment’s internal quality system, internal calibration procedures and meet the requirements of standards NEN2649, NEN3680 and/or NEN5140.

The calibration interval may vary from customer use and different conditions. All calibrations are verified at a moment in time; and confirmed within controlled temperature and humidity specified standards. Please note, that improper use of the apparatus (e.g. dropping) may cause loss of calibration.

The calibration of a CPT measuring instruments normally takes 1 day. When a measuring instrument is to be repaired, it has to be recalibrated as well.


Please consult the down-loadable document (see right column) for recommended maximum calibration intervals.

NOTE: Also measuring instruments manufactured by other companies can be calibrated by Gouda-Geo.