Are the sensors supplied with a calibration certificate?

Differences between "test report", "factory calibration certificate", "DAkkS calibration certificate"

The sensors are delivered by default with a test protocol.
Optionally, a factory calibration certificate or a DAKKS calibration certificate can be ordered.
All 3 variants contain the "characteristic value" (the slope of the characteristic), the "zero signal" of the sensor in the unmounted state, and the connection resistance. In addition, an insulation test is always carried out and confirmed.

Test Protocol

In the test protocol, the slope of the characteristic is determined in a 2-point measurement: output signal at 0% force, output signal at 100% force. The difference is reported as a so-called "characteristic value". ("To the zero signal adjusted output signal at 100% load").

The zero signal of the sensor in the unmounted state is used for information: It changed strongly, then this could indicate an overload, or on material fatigue by high number of load changes with e.g. 100% amplitude. Attention: In the characteristic value, the zero signal is already considered at 0% load.

Factory Calibration Certificate   

Optionally, a factory calibration certificate is created for order. In contrast to the test report, this contains:

  • Proof of linearity by a 5-point measurement
  • Proof of reproducibility through 3 measurement series in unchanged installation situation
  • The detection of the zero signal return error (zero signal after discharge).
  • If possible, a conformity check  of the sensor "OK", "not alright", ...
  • Proof of traceability of test equipment to national / international normal
  • The determination of the measurement uncertainty
  • The factory calibration certificate is carried out according to the standard DIN / EN / ISO 17025 in our (not yet) accredited calibration laboratory of ME-Meßsysteme GmbH.

Dakks calibration certificate  

  • The following differences exist on the factory calibration certificate:
  • The implementation takes place in a (previously external) accredited calibration laboratory.
  • A 6- or 11-point calibration according to the directive DKD-R 3-3a is carried out.
  • At least 4 measurement series are performed.
  • Measuring series in unchanged and two measurement series are carried out in the changed installation situation. The repeatability in altered and unchanged installation position is detected.
  • Measuring series in ascending and descending load stages are performed. As a result, the hysteresis can be determined.