ABB AWT420 Operating Instruction page 91

AW T4 2 0 | U N I V E R S A L 4 - W I R E , D U A L- I N P U T T R A N S M I T T E R | O I/A W T4 2 0 - E N R E V. B
NAMUR Diagnostic
icon message
S(n):
PV Out of Limits
S(n):
Internal Temp Out
of Range
S(n):
Excess Light
S(n):
Service Due
S(n):
Replace Wiper
S(n):
Replace Wiper
S(n):
Service Overdue
S(n):
LED Expired
Cause
Process value (PV) measured is outside the
specified limits of the sensor.
Refer to the sensor data sheet to determine
the operating range.
Internal temperature of the turbidity sensor is
outside its recommended operating range.
This may cause the measurements to be
inaccurate.
The turbidity sensor determines turbidity using
Nephelometric detection, by measuring the
amount of light scattered by the sample at 90°
from the direction of illumination.
Excessive ambient light can interfere with this
and result in inaccurate readings.
The turbidity sensor requires servicing.
The sensor performance degrades over time
and servicing is required to maintain accuracy.
The wiper blade on the turbidity sensor is
reaching the end of its expected useful life.
Measurement quality may be affected due to
inadequate cleaning.
The wiper blade on the turbidity sensor has
reached the end of its expected useful life.
Measurement quality may be affected due to
inadequate cleaning.
The turbidity sensor requires servicing.
The sensor performance degrades over time
and servicing is required to maintain accuracy.
This LED in the sensor has reached the end of
its expected lifespan, and so is likely to fail.
Recovery action
Check the process and the position of the sensor.
If PV Out of Limits is consistently active it may be necessary to replace
the sensor with an alternative with a wider, or more appropriate
operating range. Contact local service organization for potential
solutions.
Reposition the sensor to avoid extreme temperatures.
Ensure that the ambient temperature of the sensor is within its
operating range. 0 to 60 °C [32 to 140 °F].
If Internal Temperature Out of Range persists, contact local service
organization.
Shade the sensor, or if possible move the sensor to a location where
it is not affected by ambient light.
Contact local service organization.
Replace wiper and Reset Sensor Lifetime in Sensor Setup.
Replace wiper and Reset Sensor Lifetime in Sensor Setup.
Contact local service organization.
Contact local service organization.
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