Appendix B - Calibration Diagnostics; During Calibration; Low Sensor Efficiency - ABB 9438 User Manual

APPENDIX B – CALIBRATION DIAGNOSTICS
The transmitter can be configured to enable the current output signal to indicate certain calibration diagnostic information.
If the option for diagnostics is selected within the Set Up Retransmission scrolls, then the current output will indicate when a
calibration is taking place, and also will indicate if the sensor is giving Low Sensor Efficiency.
B.1 During Calibration
The current output value will be maintained during a calibration, but the output will pulse from the maintained value to 0%, depending
upon a programmable Cal Pulse period.
The Calibration Pulse period can be programmed 15, 30, 45 seconds, 1, 2, 3, 4, 5 minutes.
This will continue for the full duration of the calibration, exposing the sensor to air, and the recovery period.
At the end of the recovery period, if the response is good, the instrument will go back on line and the current output will become live.
100
Cal Pulse
50
0
Expose to Air Recovery Period
Time
Fig. B.1 During Calibration
B.2 Low Sensor Efficiency
If the output from a sensor is found to be below a predetermined level during a calibration (i.e. Low Sensor Efficiency) the calibration
will not be accepted. The current output immediately goes above the full scale value, and will continue to pulse on a programmable
Mark/Space basis.
The time for the Mark and Space periods can be programmed separately to 30 seconds, 1, 2, 3.....10 minutes.
100
Space
Mark
(30 s to 5 min)
(30 s to 5 min)
50
0
Expose to Air
Time
Fig. B.2 Low Sensor Efficiency
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