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5.4.3.). Select the PTC device. A window appears showing the calibration pa-
rameters for the device.
CALIBRATE DEVICE: TCS
AMP GA: 1
OS 1: 0.0007
OS 2: 0.0005
GA 1: -0.2138
GA 2: -0.2134
CJ 1: 0.273
New values can be entered for the parameters using the numeric buttons and
pressing ENTER. The buttons can be used to move between parameters.
12.4.3
Calibration Procedure
Calibration is performed in two steps. First the voltage measurement is cali-
brated then the internal CJC is calibrated. The equipment required are a pro-
grammable voltage source, a precision voltmeter with an accuracy of 10 ppm or
better, a thermocouple (preferably type E), and a temperature source between 0
and 30°C. The combined accuracy of the reference thermocouple and tempera-
ture source must be 0.012°C or better between the reference temperature and
ambient temperature. At each step during the calibration procedure the readings
should be allowed to settle for at least two minutes before recording the mea-
surement. Also, the 2565 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 Input 1, set it for 0 mV, and measure the
voltage with the 1560 (using channel 1) and the voltmeter simulta-
neously. Adjust the OS 1 parameter by subtracting the measured error.
For example, if the 1560 measures –0.0006 mV, adjust the OS 1 parame-
ter by adding 0.0006 to it. If it was previously 0.0000 it should now be
0.0006.
2.
Connect the voltage source to Input 2, set it for 0 mV, and measure the
voltage with the 1560 (using channel 2) and the voltmeter simulta-
neously. Adjust the OS 2 parameter by subtracting the measured error.
3.
Connect the voltage source to Input 1, set it for 100 mV, and measure the
voltage with the 1560 (using channel 1) and the voltmeter simulta-
neously. Adjust the GA 1 parameter by subtracting the measured error.
For example, if the input is exactly 100.0000 mV and the 1560 shows
100.2953 mV, the GA 1 parameter should be adjusted by subtracting
0.2953 from it. If it was previously 0.0000 it should now be –0.2953.
12 2565 Precision Thermocouple Module
$
Calibration
153
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