Emerson Process Management OXYMITTER 4000 Alarms O2 Cell Open, Fault 10, High Cell mV

Instruction Manual

IB-106-340C Rev. 4.1 July 2004

Hazardous Area Oxymitter 4000

	HEATER T/C
DIAGNOSTIC	HEATER	SW2
ALARMS	O2 CELL	ON
	CALIBRATION

CALIBRATION RECOMMENDED

j. Fault 10, High Cell mV

Figure 8-12shows 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). The upper view also

shows J1 and test points TP1 through TP6,

located on the microprocessor board, below

TEST

POINTS

INC INC

HIGH LOW

GAS GAS

DEC DEC

O2 CELL mV +

O2 CELL mv - HEATER T/C + HEATER T/C -

CAL

TEST GAS + PROCESS - % O2

TP1 TP2 TP3 TP4

TP5 TP6

J1 RED YEL GRN ORG

the membrane keypad or the LOI module.

Membrane Keypad. When Fault 10 is

detected, the O2 CELL flashes once,

pauses for three seconds, and repeats.

1. Using a multimeter, measure across

TP1+ to TP2-. If you measure 204 mV

to 1 volt DC, the cell reading is due to

high combustibles. This is a self-

clearing alarm, once the combustible

conditions go away. If you measure

1.2 VDC, the cell wires, either orange

KEYPAD

Alarms

O2 Cell Open

LOI 37260028

Figure 8-12. Fault 10, High Cell mV

	or green, have become detached from
	the input.
2.	One possible cause is connector J1.
	The orange or green wire has come
	loose from the crimped connection.
3.	The platinum pad could also be at fault.
	The pad could have broken free from
	the back of the cell.
4.	Replace heater strut per paragraph
	9-4g,Heater Strut Replacement. If
	necessary, replace the cell and flange
	assembly per paragraph 9-4h,Cell
	Replacement.

LOI. When Fault 10 is detected, the LOI displays the “O2 Cell Open” message.

1.Remove power. Unscrew and remove the LOI module from the electronic assembly.

2.Reconnect power to the Oxymitter 4000.

3.Perform the diagnostic steps 1 through 4 shown for the membrane keypad.

8-14 Troubleshooting Rosemount Analytical Inc. A Division of Emerson Process Management