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Maintenance
Calibrating RTD Inputs
Step
1
Perform the appropriate EMF calibration as described above.
2
Using the same input, connect a precision variable resistor to the RTD input (Figure 8-1). The A and
B leads must be of equal resistance (length).
3
For standard inputs, set the resistor to 100 ohms. Select RTD CALIBRATE 100 OHMS and press
Enter. The message CALIBRATING will appear until the RTD low range calibration is complete.
Repeat this step using 500 ohm resistor and RTD CALIBRATE 500 OHMS.
4
For 10 ohm copper inputs, set the resistor to 10 ohms. Select RTD CALIBRATE 10 OHMS and
press Enter. The message CALIBRATING will appear until the RTD low range calibration is
complete. Repeat this step using 25-ohm resistor and RTD CALIBRATE 25 OHMS.
5
Press Menu when AI calibration is complete to return to the main Maintenance menu.
8.5 Calibrate Analog Outputs
For VAT calibration, a precision voltmeter is required. For CAT calibration, a precision milliammeter or a
precision resistor and voltmeter is required.
WARNING
Disconnect power to all terminals before connecting or disconnecting calibration leads. Hazardous
voltage is present on the mains terminals and may be present on other terminals. More than one switch
may be required to de-energize the unit before servicing.
ATTENTION
Time-stamp and description of successful calibrations are stored to disk in the Event File.
ATTENTION
If you are calibrating an analog output that was changed from a CAT to a VAT or vice versa, make sure you
put the instrument online for several seconds before calibrating.
258
Table 8-3 Calibrate RTD Input Procedure
Action
Figure 8-1 RTD Calibration Connection
VPR & VRX – User Manual
A
B
C
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