ABB XSeries G4 6200, User Manual, Page: 137 / 168

2104349 rev. AD Page 5
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2) Disconnect the RTD from the termination board, if not already done.
3) Set the DMM to 200 mVDC.
4) Select the RTD test resistance value by selecting the resistor test
connection from the FCU Diagnostic kit, or make one using a resistor
appropriate for the unit.
- Substitute the RTD probe wiring by connecting either a 100 OHM or
123 OHM resistor across connector terminals 3 and 4.
- Connect a jumper wire between terminals 2 and 3.
- Connect a jumper wire between terminals 4 and 5.
5) Clip the positive lead of the DMM to the upper side of the RTD test resistor.
6) Clip the negative lead of the DMM to the lower side of the RTD test resistor.
7) Supply power to the unit.
8) Once running, the measured value across the RTD test resistor should be
either:
- 100 OHM Resistor
– Min of 100mv to a maximum of 125mv
- 123 OHM Resistor
– Min of 123mv to a maximum of 155mv
9) The RTD measurement temperature on the G4 EX display should read
either:
- 100 OHM Resistor
– 31.0°F to 33.0°F
- 123 OHM Resistor
– 140.8°F to 142.8°F
10) If either of the measured values are outside of the range, remove power and
replace the RTD.
11) Return power, and perform steps 9 and 10 again. If either of the measured
values are outside of range, remove power, and replace the main
termination board.
12) Return power, and perform steps 9 and 10. If either of the measured values
are outside of the range, remove power, and replace the EXIMV.
5.2.6 RTD Impedance test
If readings from the RTD are still suspect following the RTD Probe test, follow the
instructions below to test the current source on the termination board to verify that
it is receiving power.
5.2.6.1
Required equipment
- Ice Bath
- Digitial MultiMeter
5.2.6.2
Step-by-step instructions
1) Immerse RTD probe in ice bath.
2) Perform a continuity check between any two similarly colored wires.
Measured resistance should be 1 OHM or less.
3) Perform a continuity check between any two dissimilar colored wires.
Measured resistance should be approximately 100 OHMs.
4) Perform a continuity check between shield wire and any other wires.
Measured resistance should be in the Megohm range.