Thermocouple Calibration And Key Issues Of Accuracy

A thermocouple may be defined as a temperature sensor derived from joining two different metal wires together at one end. The junction produces a voltage when there is a temperature variation at the junction and this voltage can subsequently be read as temperature. Their basic principle is quite ornamental since they are rugged and work over broad temperature limits.

Reasons for Accuracy Degradation

The accuracy of thermocouples can be affected due to a number of reasons. They include:

Reference Junction Compensation: The voltage produced by a heating coil thermocouple relies on the temperature difference of the measuring junction to the reference junction. Proper compensation techniques are required to ensure that all temperature readings are correctly recorded.

Wiring and Connection Quality: Shoddy connections or failure to wire correctly cause errors. The use of good materials and proper connection would go a long way in enhancing the quality of measurement.

Environmental Conditions: Passive design structures such as shielding, insulation and encapsulation can only offer protection to thermocouples to an extent. Moisture, dust, vibrations and metal vapors if any will hamper the efficiency of the thermocouple and hence the thermometers. Specially designed thermocouples must be chosen to reduce these negative consequences.

Best Practices for Calibration

In an attempt to maximize the performance of thermocouples in terms of accuracy, the following are the practices that should be done:

Routine Calibration Timeframe: Define and comply with a maintenance procedure concerning periodic calibration relative to the application and conditions of use.

Standard Reference Material for Calibration: The reference materials that are used in calibration must be up to the set standards as they will be employed in the evaluation.

Log all Records of the Calibration Outputs: Document and maintain calibration results and adjustment of the calibration control out and other future quality controls to be conducted as planned

Understanding the process of recalibrating and the implications of this on the accuracy of temperature measurement using thermocouples is important in ensuring optimum temperature measurements in several jurisdictions. Veering away from, or utilizing poor practices of, proper calibration practices, and other possible interfering parameters, the users raised the performance of their thermocouples.

Please visit our page at VSEC if you are seeking quality thermocouples and other temperature sensors. We ensure all our products comply with the requirements of the industry and necessary precision which is important while monitoring temperature.