Thermocouple Reference Junction Accuracy Test; Thermocouple Reference Junction And Accuracy Alignment - Fluke 9190A Operator's Manual

9190A
Operators Manual

Thermocouple Reference Junction Accuracy Test

The Thermocouple Cold Junction Accuracy Test is used to collect As Found, Alignment,
and As Left data.
The Thermocouple Reference Junction Accuracy Test requires the use of a
Type-E thermocouple. This thermocouple must be put in a heat source and
controlled at a constant 25 °C throughout the duration of the test.
All Thermocouple Reference Junction Accuracy Tests are to be performed
in °C.
Perform the Thermocouple Cold Junction Accuracy Test as follows:
1. Connect the Type-E thermocouple to the thermocouple UUT connector on the
2. Set the instrument to take UUT measurements from the thermocouple input.
3. Set the instrument conversion type for the UUT thermocouple input to TC-E.
4. Let the readout stabilize for 20 seconds.
5. Take temperature measurements from the UUT thermocouple input at a 2-second
6. Calculate the average of the measurements taken. Record these results.
7. Calculate the error with the formula below. Record this result.
8. Compare the error with the specification to determine the status. Record the result.

Thermocouple Reference Junction and Accuracy Alignment

The Thermocouple Reference Junction and Accuracy Alignment process calculates a new
offset to be programmed into the instrument for the UUT thermocouple reference
junction to correct for the measured error at 25 °C.
Perform the Thermocouple Reference Junction and Accuracy Alignment as follows:
1. Locate the results of the Thermocouple Reference Junction Accuracy Test.
2. Use the calculated errors and the previous (current) offset value, and calculate the
3. Enter the new offset values into the instrument.
4. Let the readout stabilize for 20 seconds before a measurement is made.
5. Take As Left data with the steps outlined in the Thermocouple Reference Junction
4-22
instrument.
interval for a minimum of 40 samples.
Error = Average – Nominal
new offset value for the thermocouple reference junction accuracy parameter with the
formula below:
TCCRJ = TCCRJ
new previous
Accuracy Test.
Note
– Error 25 °C