ABB XSeriesG4 User Manual page 143

7.2.6 RTD Current Source (Resistive) Test
If readings from the RTD are still suspect following the RTD Probe Continuity test, follow the instructions below to test the
current source on the termination board to verify it is receiving power.
Required Equipment:
— Flow computer diagnostics kit (Part No. 2017373)
— Multi Meter (MM) w/ alligator clip leads
To perform an RTD current source (resistive) test:
Disconnect the power and communications from the main electronic panel.
Disconnect the RTD from the main electronic panel.
Set the MM to 200mVdc.
Select the RTD test resistance value by selecting the resistor test connector from FCU Diagnostic Kit, or make one
using a resistor appropriate for your unit:
- Substitute 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.
Clip the positive lead of the MM to the upper side of the RTD test resistor.
Clip the negative lead of the MM to the lower side of the RTD test resistor.
Supply power to the flow computer.
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
-
The RTD measurement temperature on the FCU display should read either:
100 OHM Resistor – 31.0°F to 33.0°F
-
123 OHM Resistor – 140.8°F to 142.8°F
-
If either of the measured values are outside of range:
- Remove the power.
- Replace the RTD (2011905-xxx).
Return the power and perform steps 9 and 10 again.
If either of the measured values are outside of range:
- Remove the power.
- Replace the main electronic panel (2102838-xxx).
Return power and perform steps 9 and 10.
If either of the measured values are outside of the range:
- Remove the power.
- Replace the XIMV.
7.2.7 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 it is receiving power.
Required Equipment:
— Ice Bath
— Multi Meter
To perform an RTD impedance test:
144 XFC G4 2103335 Rev AB