A calibration of force transducers is merely a comparison with a reference and therefore does not involve any intervention in the transducer itself.

During factory calibration, the relationship between the mechanical input variable (e.g. compressive or tensile force) and the electrical output variable (e.g. current value) is compared with a DKD-calibrated reference and documented.

The question of when recalibration should take place depends on the type and duration of use. 
For example, the following can be considered

• Continuous use / number of operating hours
• Extreme environmental conditions (temperature / humidity / dirt)
• Strongly changing load conditions
• Safety-relevant area of application

The recalibration interval is determined by the user. It must be checked whether internal specifications already exist (e.g. in the quality management manual) or whether a specific interval must be adhered to in accordance with a general standard.

In accordance with the user-defined requirements for the measurement properties, recalibration is required, 

for example 

• after a selected period of time or
• after a certain number of load changes or
• in rare cases, both before and after each measurement

be carried out. 

In-house long-term observations and comparison with several identical sensors can also help to adjust calibration intervals.

It is recommended to carry out a functional check (without protocol) or a recalibration (with calibration protocol) every 2 years. In addition, a recalibration should always be carried out if a significant zero point deviation has been detected in the dismantled state or if the force transducer has been exposed to loads for which it was not designed. 

For example

• Mechanical stress during installation or dropping
• Non-observance of the intended installation position 
• Exceeding the maximum utilisation force 
• Exceeding the temperature conditions 
• Carrying out unauthorised interventions for conversion / repair purposes.