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© 2021 All rights reserved. Data subject to change without notice.
LPT - Operation Manual
Rev. E | 2021.03
If the sensitivity of the sensor is calculated out of range more than the OVER can compensate for,
the in
ternal LED will turn on solid, the front LED will remain off and the current loop will output 20
mA indicating the sensor cannot be calibrated. You can try to recalibrate, starting from step 2, to
confi rm the procedure was followed correctly and this may correct the fault.
If this does not correct the fault, please contact our Technical Service Department at help@cetci.
com.
To exit calibration mode, remove Jumper-2 from the CAL position and return it to the IDLE position.
If the digital multi-meter leads are attached to test points TP-1 and TP-2, the measured voltage will
start moving towards the voltage calculated for the span gas value.
8.3 Calibrating an Oxygen Sensor
When calibrating an Oxygen sensor, the process is reversed. You need to do the span fi rst and then
the zero.
NOTE
: Oxygen sensors have a 2 or 3 year life span. If the reading before starting the calibration has
been dropping over the past couple of weeks a calibration may only last several days if the sensor
is expiring. The calibration may complete but the reading will start to drop over the next couple of
days .
The calibration procedure of the LPT is jumper automated (there are no potentiometers to adjust).
Monitoring the calibration with a volt meter at TP1 and TP2 is optional but suggested. The range
of 0 - 4.0 VDC is equal to the full measurement range of the sensor. O2 sensor has a standard
measurement range of 0 - 25% vol. Therefore, 4.0 VDC = 25% VOL O2, 3.44 VDC = 20.9% VOL O2.