Standard Guide for Calibration and Use of Thermocouple Reference Junction Probes in Evaluation of Electronic Reference Junction Compensation Circuits

Importancia y uso:

5.1 Many electronic instruments that are designed to be used with thermocouples use some method of reference junction compensation. In many industrial applications it may be impractical to use a physical ice bath as a temperature reference in a thermocouple circuit. The instrument must therefore be able to measure the temperature at the point of electrical connection of the thermocouple and either add or subtract voltage to give a corrected equivalent of what that thermocouple would indicate had there physically been 0 °C reference junctions present in the circuit. There are two types of instruments that generally apply these techniques: electronic thermometer readouts that use a thermocouple as the sensor, and calibrators designed to calibrate these digital thermometer readouts. Additionally, the probe and circuit described in this guide can be used with a voltmeter to emulate a thermometer or a voltage source to calibrate temperature-indicating instrumentation. In all cases the probe must be calibrated if traceability or an uncertainty analysis, or both, is required.

Subcomité:

E20.14

Referida por:

E0344-23

Volúmen:

14.03

Número ICS:

17.200.20 (Temperature-measuring instruments)

Palabras clave:

calibration; PRT; reference junction compensation; reference junction probe; Seebeck coefficient; SPRT; thermocouple; verification;