Calibration
9190A Input Panel Calibration 4
4-23
Thermocouple Accuracy Alignment
The Thermocouple Accuracy Alignment process calculates new offsets to be
programmed into the instrument for the UUT thermocouple input to correct for measured
errors at specific points over the voltage range of the input.
Perform the Thermocouple Accuracy Alignment as follows:
1. Locate the results of the Thermocouple Accuracy Tests.
2. With the calculated errors and the previous (current) offset values, calculate the new
offset values for each thermocouple accuracy parameter with the formulas below:
TCC0
new
= TCC0
previous
– error0mV
TCC100
new
= TCC100
previous
– (1.0 x error50mV) – (0.5 x error100mV)
3. Enter the new offset values into the instrument.
4. Let the readout stabilize for 20 seconds after the new offset values are entered before
a measurement is made.
5. Take As Left data with the steps outlined in the Thermocouple Accuracy Test.
4-20 mA Input Calibration
Table 4-15 shows the basic sequence of tests to be performed on the 4-20mA input.
Table 4-15. 4-20 mA Input Calibration Steps
# Test Name Nominal(s) mA Notes
1 4-20 mA Accuracy Test 0, 4, 12, 20, 22 As Found/Alignment data
2 4-20 mA Accuracy Alignment - Calculate offsets with
Alignment data
3 4-20 mA Accuracy Test 0, 4, 12, 20, 22 As Left data
4 24 V Source Test 24 volts Functional test
4-20 mA Accuracy Test
The 4-20 mA Accuracy Test is used to collect As Found, Alignment, and As Left data.
Note
All 4-20 mA Accuracy Tests are to be performed in mA.
Perform the 4-20 mA Accuracy Test as follows:
1. Connect the current source to the 4-20 mA UUT input connector.
2. Set the 4-20mA input to take UUT measurements.
3. Set the mA input LOOP POWER setting to DISABLED.
4. Set the current source to supply 0 mA.
5. Let the readout stabilize for 20 seconds.
6. Take mA measurements from the UUT mA input at a 2-second interval. Take a
minimum of 40 samples.
7. Set the current source to supply 4 mA.
8. Let the readout stabilize for 20 seconds.
To Next Page
Loading...
