Emerson 4000 manual Alarms O2 Cell Open, Fault 10, High Cell mV

Instruction Manual

IB-106-340 Rev. 3.0

December 2003

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

CALIBRATION RECOMMENDED

Oxymitter 4000

j. Fault 10, High Cell mV

Figure 8-12shows the electronic assembly

for an Oxymitter 4000 with a membrane

keypad (upper view) and an 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 the membrane keypad or the LOI

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

module.
Membrane Keypad. When Fault 10 is de-
tected, the O2 CELL flashes once, pauses
for three seconds, and repeats.
1.	Using a multimeter, measure across
	TP1+ to TP2-.
2.	If you measure 1.2 VDC, the cell wires,
	either orange or green, have become
	detached from the input.

KEYPAD

Alarms

O2 Cell Open

LOI 37260028

Figure 8-12. Fault 10, High Cell mV

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

2.Reconnect power to the Oxymitter 4000.

3.Perform the diagnostic steps 1 through 5 shown for the membrane keypad.

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