Emerson Process Management IB106-340 instruction manual Fault 2, Shorted Thermocouple

Oxymitter 4000

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

CALIBRATION RECOMMENDED

Instruction Manual

IB-106-340 Rev. 2.4

April, 2001

b. Fault 2, Shorted Thermocouple

The HEATER T/C LED flashes twice,

pauses for three seconds, and repeats

(Figure 5-2).

1. Using a multimeter, measure across

TP3+ and TP4-.

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

22220034

2.	If the reading is 0 ±0.5 mV, then a
	shorted thermocouple is likely.
3.	Remove power and disconnect J1.
4.	Measure from TP3+ to TP4-. The
	reading should be approximately 20
	Kohms.
5.	If so, the short is not on the PC board.
	See paragraph 6-7,Heater Strut Re-
	placement.

Figure 7-2. Fault 2, Shorted Thermocouple

7

Rosemount Analytical Inc. A Division of Emerson Process Management Troubleshooting 7-5