Emerson Process Management OXYMITTER 4000 - Manual (Page 105)

Instruction Manual
IB-106-340C Rev. 4.1
July 2004
Rosemount Analytical Inc. A Division of Emerson Process Management Troubleshooting 8-9
Hazardous Area Oxymitter 4000
LOI
KEYPAD
DIAGNOSTIC
ALARMS
TEST
POINTS
HEATER T/C
HEATER
O2 CELL
CALIBRATION
CALIBRATION RECOMMENDED
O2 CELL mV +
O2 CELL mv -
HEATER T/C +
HEATER T/C -
INC INC
DEC DEC
HIGH
GAS
LOW
GAS
CAL
TEST GAS +
PROCESS -
% O2
SW2
TP1
J1
TP2
TP3
RED YEL GRN ORG
TP4
TP5
TP6
ON
37260023
Alarms
O2 Heater Open
Figure 8-7. Fault 5, Open Heater
e. Fault 5, Open Heater
Figure 8-7 shows the electronic assembly
for a Hazardous Area Oxymitter 4000 with
a membrane keypad (upper view) and a
Hazardous Area Oxymitter 4000 with an
LOI (lower view).
Membrane Keypad. When Fault 5 is
detected, the HEATER LED flashes once,
pauses for three seconds, and repeats.
1. Remove power.
2. Remove the electronic assembly per
paragraph 9-4c, Electronic Assembly
Replacement.
3. Using a multimeter, measure the re-
sistance across the terminals of heater
connector, J8.
4. The measurement should be approxi-
mately 72 ohms. If the heater is open,
see paragraph 9-4g, Heater Strut
Replacement.
LOI. When Fault 5 is detected, the LOI dis-
plays the “O2 Heater Open” message.
1. Remove power. Unscrew and remove
the LOI module from the electronic as-
sembly.
2. Perform the diagnostic steps 2 through
4 shown for the membrane keypad.
8