Teledyne LXT-280 - Manual (Page 50)

Maintenance LXT-280
Teledyne Analytical Instruments 40
Sensor not wired properly
Using the proper wiring
diagram, verify that the
sensor is properly wired to
the transmitter.
Sensor is not wired
properly.
Verify that the sensor is
wired properly to the
transmitter using the
applicable wiring diagram.
Sensor and the electrode
are not properly submersed
in the process. Verify that the sensor body
and the electrode are
submersed in the process.
Electrode cartridge is not
fully engaged in the sensor
body Check cartridge to see that
it is fully engaged in the
sensor body.
TC Module in sensor is not
functioning properly
Observe temperature
reading on display. If it
shows a major discrepancy
to the actual temperature,
measure across TC wires
on sensor — it should be
3000 ohms at 25°C.
Signal conditioner not
properly engaged in the
rear of the sensor body.
Verify that the signal
generator is properly
engaged in the rear of the
sensor body.
Temperature trim not
properly adjusted
Verify temperature display
and temperature trim
adjustment.
Sensor output is off-scale
Transmitter or analyzer
failure
Verify that the sensor is not
the cause of the problem.
Troubleshoot the
instrument and correct the
problem
The DO reading is over-
sensitive or under-sensitive
with temperature changes.
The locus point is not
correct
Verify the correct locus. If
using Teledyne sensors,
the locus must be -17°C.
A troubleshooting procedural recommendation:
In troubleshooting an analytical measurement loop, it should be
kept in mind that the majority of the problems encountered with the
measurement are due to failures of the sensing element. Therefore, it is
recommended that the troubleshooting procedure start with the sensing
end of the measurement and work backwards to the instrument.