Emerson 3081FG instruction manual Fault 3, Shorted Thermocouple

Model 3081FG

Instruction Manual

IB-106-3081 Rev. 1.5 September 2002

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26020026

Figure 6-7. Fault 3, Shorted Thermocouple

c. Fault 3, Shorted Thermocouple

The thermocouple connections are shorted.

The fault displays as shown in Figure 6-7.

1. Allow adequate time for the oxygen

26020027

Figure 6-8. Fault 4, High Probe Temperature

d.Fault 4, High Probe Temperature

The probe’s temperature has exceeded the maximum cell temperature setpoint. The fault displays as shown in Figure 6-8.

probe to reach operating temperatures.

Probe temperatures below approxi-

mately 500°C (932°F) may result in this

fault.

1. If the probe temperature exceeds the maximum cell temperature setpoint, the 4-20 mA signal output will become invalid and go to the default value.

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2.	Refer to Figure 6-4.Using a multime-
	ter, measure between terminals 8(-)
	and 10(+).
3.	If the multimeter reading, in voltage
	mode, is between -0.5 and +0.5 mV,
	the thermocouple is shorted.
4.	If the thermocouple is shorted, replace
	the oxygen probe per paragraph 5-2.
5.	If the thermocouple is not shorted, then
	replace the PC board stack assembly
	per paragraph 5-1.

2. Verify that the upper cell temperature setpoint is configured as desired under the PROGRAM MENU (see Section 3,

STARTUP AND OPERATION).

Rosemount Analytical Inc. A Division of Emerson Process Management Troubleshooting 6-5