Emerson 3081FG instruction manual Section Troubleshooting, Probe Life, Impedance, Ω

Models: 3081FG

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Model 3081FG

Instruction Manual

IB-106-3081 Rev. 1.5 September 2002

SECTION 6

TROUBLESHOOTING

Install all protective equipment covers and safety ground leads after trouble- shooting. Failure to install covers and ground leads could result in serious injury or death.

6-1 GENERAL

This troubleshooting section describes how to identify and isolate faults that may develop in the Two-Wire In Situ Oxygen Analyzer.

6-2 PROBE LIFE

The zirconium oxide technology for measuring oxygen is very stable and should provide accu- rate service for several years.

Life of the probe is negatively impacted by:

Continued operation at elevated tempera- tures above 1300°C (2372°F).

Operation in processes that contain high levels of sulfur, SO2, or other acidic com- pounds.

Operating conditions with simultaneously high levels of SO2 and low levels of O2 are particu- larly damaging.

The health and accuracy of a given cell is closely related to the resistance, or impedance, of the cell. Figure 6-1 illustrates that the amount of output from a cell for a given O2 value (repre- sented as slope) will remain very stable to the point where cell impedance increases to ap- proximately 100 ohms.

SLOPE (mV/Dec)

50

6

NORMAL

DETERIORATED PERFORMANCE,

DETERIORATED PERFORMANCE,

OPERATIONAL

SLOW RESPONSE,

SLOW RESPONSE,

CONDITIONS

HIGH MEASUREMENT ERROR

HIGH MEASUREMENT ERROR.

 

 

CONDUCT FREQUENT CALIBRA-

 

 

TION CHECKS.

48.0<S<51mV/Dec

45.0<S<48mV/Dec

S<45mV/Dec

IMPEDANCE,

26020059

Figure 6-1. Slope vs. Impedance

Rosemount Analytical Inc. A Division of Emerson Process Management

Troubleshooting 6-1

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Emerson 3081FG instruction manual Section Troubleshooting, Probe Life, Impedance, Ω