Emerson 3081FG - Manual (Page 60)

Instruction Manual
IB-106-3081 Rev. 1.5
September 2002
6-2 Troubleshooting Rosemount Analytical Inc. A Division of Emerson Process Management
Model 3081FG
IMPEDANCE,
SPEED
OF
RESPONSE
(t
),
sec
90
0
26020060
100
200
300
400
500
AIR TO 0.4% O
2
0.4% O TO AIR
2
Ω
Figure 6-2. Speed of Response
Frequently conduct calibration checks to look for
the following conditions:
• Continued degradation of cell slope.
• Sluggish response. (Note how long it takes
the cell to respond to the application of cali-
bration check gases.) See Figure 6-2.
The slope will be valid only for the process tem-
perature at which the calibration check gases
are flowed, so no adjustments to the electronics
are made as a result of a calibration check.
Note that cells exposed to temperatures above
1300°C (2372°F) may lose the ability to meas-
ure accurately and respond quickly when re-
turned to the lowest end of the operating
temperature range [550°C (1022°F)].
6-3 FAULT INDICATIONS
The fault conditions for the Two-Wire In Situ
Oxygen Analyzer will be indicated by the faulted
operation display as shown in Figure 6-3. This
screen displays when a fault that invalidates the
O
2
reading is present. When the error is cor-
rected, the screen will return to a normal opera-
tion display unless another error exists.
%
mA
26020022
Figure 6-3. Faulted Operation Display