Calibration is the testing of a temperature sensors output compared to the measurement of more accurate equipment or known temperature for quality purposes. Calibration verifies sensor accuracy is within defined and expected tolerances.
There are many different options and types when calibrating temperature sensors.
Temperature sensors can be calibrated by a UKAS accredited calibration service, which is the national body for the accreditation of testing and calibration laboratories. Alternatively, a temperature sensor can be calibrated to Traceable Calibration, which is very often is an acceptable method of calibration. Traceable Calibration means there is an unbroken chain of documentation back to national standards.
Calibration can be conducted as numerous stages depending on customer requirements:
- Temperature sensor cable and wire can be batch calibrated at the start and end of its length to give a representative sample of the total reel or coil and to show variations along its length.
- After temperature sensors have been manufactured, a sample of the sensors can be calibrated to again show a representation of how the total number of sensors will perform.
- Each individual sensor can be calibrated to ensure all manufactured products fall into desired error limits.
- When wire, cable or sensors are calibrated they can be checked at numerous temperatures. For Traceable Calibration it is common to test a sensor at three to five different temperatures from its minimum and maximum operating range. UKAS calibration will include many more points of calibration. Each calibrated temperature point will add another level of surety to the calibration.
Calibration tests a temperature sensor or instrument by comparing its output to higher accuracy sensor or instrument which is called a reference sensor or reference instrument. Calibration certificates are provided to show how much the calibrated sensor deviates from the reference sensor.
Calibration ensures that temperature sensors and instrumentation are performing as required. Sensors or equipment that is uncalibrated will result in less process control. Which could result in increased costs or reduced quality. Temperature sensors and instrumentation are regularly recalibrated on a set schedule to ensure they are performing as intended.