In this article, we will discuss the temperature sensor calibration procedure. The temperature sensor calibration is a must for ensuring the accuracy in measurement. The wrong temperature reading may cause catastrophic damage to the machinery and the process.
The frequency of calibration checking of temperature sensors must be once in a year. After calibration of temperature sensor, the accuracy check results must be available in record. This information helps in finding the drift in accuracy in the next calibration.
This accuracy check is generally not performed at the site. The calibration report is generally available with the instrumentation documentation of the temperature sensors manufacturers. Or buyer may ask manufacturer to provide temperature sensors calibration report.
Calibration Procedure
The temperature sensor calibration procedure is;
- Fill a container with water and bring the water temperature down to the water body’s temperature to be measured. You can use ice or warm water to adjust the temperature.
- Take a thermometer that has traceability certificate of National Institute of Standards and Technology (NIST). Place the thermometer and the temperature sensor(Device under test) into the the water. Wait until the temperature readings of both the sensors get stabilized.
- After stabilizing of the temperature reading of the standard thermometer and the sensor, note down the readings. The temperature sensor reading must be identical to the reference thermometer temperature within the accuracy of ±O.2°C. If the temperature variation of reference thermometer and the temperature sensor is beyond ±O.2°C, the sensor must be replaced.
- Now, raise the water temperature up than the water body. Wait till the temperature readings of both the sensors get stabilized.
- After stabilizing of the temperature reading of the standard thermometer and the sensor, note down the readings. The temperature sensor reading must be identical to the reference thermometer temperature within the accuracy of ±O.2°C. If the temperature variation of reference thermometer and the temperature sensor is beyond ±O.2°C, the sensor must be replaced.