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Performance Testing and Calibration
Performance Tests
4
4-11
4-9. Open Thermocouple Response Test
Use the following procedure to test the open thermocouple response:
1. Switch OFF power to the instrument and disconnect all high voltage inputs.
2. Remove the Input Module from the rear of the instrument. Open the Input Module
and connect test leads to the H (high) and L (low) terminals of channel 1. Reinstall
the Input Module into the instrument.
3. Reconnect power and switch the instrument ON.
4. Connect the test leads from the Input Module to an 820 ohm resistor.
5. Select the temperature function and K thermocouple type for channel 1. Then press
MON.
6. The value displayed should approximate the ambient temperature.
7. Replace the 820-ohm resistor with a 4-kilohm resistor to simulate a high resistance
or open thermocouple.
8. Verify a reading of "otc".
9. The Open Thermocouple Response Test is complete. However if you desire to
perform this test on any other Input Module channel (2 through 20) repeat steps 1
through 8, substituting the appropriate channel number.
4-10. RTD Temperature Accuracy Test
The following two RTD Temperature Accuracy Tests are different in that one uses a
Decade Resistance Source and the other uses an RTD. Only one of the tests needs to be
performed to verify operation.
4-11. RTD Temperature Accuracy Test (Using Decade Resistance Source).
Verify that the channel 0 accuracy verification tests for dc volts and 300-ohm range meet
minimum acceptable levels.
1. Switch OFF power to the instrument and disconnect all high voltage inputs.
2. Remove the Input Module from the rear of the instrument. Open the Input Module
and connect a pair of test leads (keep as short as possible) to the H (high) and L
(low) terminals of channel 1. For 4-terminal performance testing, connect a second
pair of test leads to the H (high) and L (low) terminals of channel 11. Reinstall the
Input Module into the instrument.
3. Connect the channel 1 test leads to the Output HI and LO terminals on the Decade
Resistance Source. For 4-terminal performance testing, also connect channel 11’s
test leads to the Output HI and LO terminals of the Decade Resistance Source.
Connect as shown in Figures 4-1 and 4-2.
Note
4-terminal connections are made using pairs of channels. 4-terminal
measurements can only be made on channels 1 through 10. The
accompanying pairs are channels 11 through 20.
4. Switch the instrument ON.
5. Select the 4-terminal RTD temperature function, RTD type PT, for channel 1 on
Hydra.
6. Press MON. For each resistance, ensure that the display reads within the range
shown in Table 4-5.