Emerson Process Management IB106-340 instruction manual Fault 1, Open Thermocouple

Instruction Manual

IB-106-340 Rev. 2.4

April, 2001

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

CALIBRATION RECOMMENDED

Oxymitter 4000

a. Fault 1, Open Thermocouple

The HEATER T/C LED flashes once,

pauses for three seconds, and repeats

(Figure 7-1).

1. Check connector J1. Ensure the con-

nector is properly seated.

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

REDYELGRNORG

22220033

2.	Using a multimeter, measure TP3+ to
	TP4-. If the reading is 1.2 VDC ±0.1
	VDC, the thermocouple is open.
3.	Remove power. Disconnect J1. Meas-
	ure continuity across the red and yel-
	low thermocouple leads.
4.	The measurement should read ap-
	proximately 1 ohm.
5.	If the thermocouple is open, see para-
	graph 6-7,Heater Strut Replacement.

Figure 7-1. Fault 1, Open Thermocouple

7-4 Troubleshooting Rosemount Analytical Inc. A Division of Emerson Process Management