Temperature measurement is one of the most common measurements within laboratories and industries.  This is why it is important to have your temperature sensors calibrated regularly to maintain accurate data.  There are several ways that the temperature sensors can be calibrated based upon the available equipment and what is suitable for your needs.

Techniques and Methods

When calibrating a temperature sensor, you must have a known temperature to immerse the sensor in to calibrate it.  You need a proper temperature and source.

There are two techniques to calibrate a temperature sensor, one as part of a system or the sensors individually.  If the sensors are calibrated individually, they obtain a calibration report with corrections that are later entered into the electronics connected to the temperature sensor for an accurate temperature reading.  When calibration occurs as part of a system, the sensor is heated or cooled to a known temperature, and corrections are made directly to the electronics.  Within the two techniques, there are a few common methods to calibrate.

Calibration of the Electronics with a Simulator

To calibrate the electronics, a simulator takes an input temperature and simulates the corresponding voltage or resistance based upon known national tables.

This method is a fast way, as the electrical settings are instant and do not require stabilization times.

Calibrate in a Dry-Well

When calibrating the electronics and sensor with a dry-well they set it to the desired test temperature and then everything is placed in the well.  They compare the thermometer reading to the dry well’s thermometer.

When calibrating this way, the only tool that is necessary is the dry-well.  The accuracy is restricted by the calibrated accuracy of the dry-well.

Calibrating in a Dry-Well with a Reference Thermometer

The dry-well is used as the stable heat source and the thermometer is compared to a more precise thermometer placed in an adjacent hole in the well.  The calibration is traceable to the separate reference and ensures the best accuracy results.

This method is specifically more accurate and requires a more complex setup in the laboratory.

Calibration Considerations

There are multiple considerations that must be made when calibrating a temperature sensor.  The first is that they must document the information in a calibration certificate.

The reference standard must have valid traceability to National Standards.

Like any calibration, you must be aware of the total uncertainty of the process.  Specifically, when it comes to temperature calibration, the process can be the biggest uncertainty element in the total uncertainty.

Professional calibration of temperature sensors is done with temperature baths or dry well’s getting the most accurate data and calibration.

Working with an ISO 17025 Accredited Lab

SRP control systems have been helping industries with their calibration needs for the last 40 years.  If you are unsure about the best way to calibrate your temperature sensors, give them a call.  They can help your lab more efficiently as a service and product provider.