Emerson Rosemount Oxymitter 4000 Reference Manual page 123

Reference Manual
00809-0100-4340
2. Reconnect power to the transmitter.
3. Perform the recommended actions in
8.5.3 Fault 3, Reversed Thermocouple Wiring or Faulty PC
Board
The figures below show the electronic assembly for a transmitter with a membrane
keypad and a transmitter with an LOI.
The membrane keypad also shows J1 and test points TP1 through TP6 located on the
microprocessor board, below the membrane keypad or the LOI module.
Fault 3, membrane keypad
When Fault 3 is detected, the HEATER T/C LED flashes three times, pauses for three
seconds, and repeats.
Figure 8-6: HEATER T/C LED Alarm on Membrane Keypad
Recommended actions
1. Using a multimeter, measure the voltage from TP3+ to TP4-.
2. Check red and yellow wires in the J1 connector for the proper placement.
Rosemount Oxymitter 4000
If the reading is negative, the thermocouple wiring is reversed.
If the wiring is correct, the fault is in the PC board. See
Fault 2, membrane keypad.
Replace electronic
Troubleshoot
October 2019
assembly.
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