ABB Advance Optima Uras 14 - Troubleshooting: Zero Drift; Measured Value Drift

4-6 Chapter 4: Troubleshooting SHB_U14
Zero drift / Measured value drift
Indication
Zero point signal undergoes long- and/or short-term drift to positive or negative
values
Status messages
After calibration messages 4 or 16 may appear.
Details
Possible cause Measures
Calibration not performed often enough Reduce the interval between
calibrations
Sample gas line contaminated - Clean the sample gas line
- Check the sample gas line
temperature
- Check the cooler
Sample cell contaminated - Clean or replace the sample cell
- Check sample gas preparation, install
additional filters if needed
- Use aluminum cells, perform an initial
calibration of all IR detectors involved
- Configure the module thermostat and
perform initial calibration of all IR
detectors.
Sample gas path leak Check the sample gas path ahead of
and within the analyzer module for
leaks.
IR detector becoming less sensitive Replace IR detector
Defective cable between emitter/IR
detectors and IR module circuit board
Establish connection
Defective IR module circuit board Replace circuit board
Defective Sensor-CPU circuit board Replace circuit board
Defective EEPROM on Sensor-CPU
board
Replace EEPROM and/or reload data
set