Thermometer Readout User's Guide

Parameter Description
C0 Adjusts the voltage accuracy of at 0 mV
C100 Adjusts the voltage accuracy of at 100 mV
CRJ Adjusts the internal RJC accuracy
DATE Records the date the thermocouple channel was calibrated
DUE Records the date the thermocouple channel calibration expires
The calibration parameters can be accessed from the CALIBRATION function
of SYSTEM menu
9.2.2 Calibration Procedure
Calibration of each channel is performed in two steps. First the voltage mea-
surement is calibrated then the internal RJC is calibrated. The equipment re-
quired are a programmable voltage source, a precision voltmeter with an
accuracy of 10 ppm or better, a thermocouple (preferably type E), and a tem-
perature source between 0 and 30°C. The combined accuracy of the reference
thermocouple and temperature source must be 0.06°C or better between the ref-
erence temperature and ambient temperature. At each step during the calibra-
tion procedure the readings should be allowed to settle for at least two minutes
before recording the measurement. Also, the 1529 should be allowed to warm
up for at least one hour after power up prior to calibration. The recommended
procedure is as follows:
1. Connect the voltage source to the thermocouple channel, set it for 0 mV,
and measure the voltage with the 1529 and the voltmeter simultaneously.
Adjust the C0 parameter by subtracting the measured error. For example,
if the 1529 measures –0.0006 mV, adjust the C0 parameter by adding
0.0006. If it was previously 0.0000 it should now be 0.0006.
2. Set the voltage source to 100 mV and measure the voltage with the 1529
and the voltmeter simultaneously. Adjust the C100 parameter by sub
-
tracting the measured error. For example, if the input is exactly 100.0000
mV and the 1529 shows 100.2953 mV, the C100 parameter should be ad
-
justed by subtracting 0.2953. If it was previously 0.0000 it should now
be –0.2953.
3. Verify the voltage accuracy at 0, 50, and 100 mV. The accuracy must be
within the short-term voltage accuracy given in the specifications.
4. Connect the calibrated thermocouple to the thermocouple channel and
insert the thermocouple into the temperature source. Measure the tem
-
perature with the 1529 (be sure to program the channel with the correct
thermocouple type). Adjust the CRJ parameter by subtracting the mea
-
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9 Calibration
Thermocouple Calibration
Table 14 Calibration Parameters