Endress+Hauser Memosens COS51E, Operating Instructions Manual

Page: 28 / 48

Diagnostics and troubleshooting Memosens COS51E
28 Hauser
8 Diagnostics and troubleshooting
8.1 Checking the sensor
Only authorized and trained personnel may test the sensor. A multimeter (voltage,
resistance) is required for testing.
Test Required action Set point
Slope check Expose the sensor to air and dry with a paper towel. approx. 102 % SAT
Zero-point check Immerse the sensor in COY8 zero-point gel or nitrogen. Display close to 0 mg/l (0 % SAT)
In the event of deviations from the setpoint, perform troubleshooting →  28 or
contact the Service department.
8.2 General troubleshooting
‣
If one of the following problems is present:
Check the measuring system in the order shown.
Problem Test Remedial action
No reading, sensor not
responding Power supplied to the
transmitter?
‣
Establish the power supply.
‣
Switch on channel on transmitter.
Sensor cable connected
correctly?
‣
Establish correct connection.
Insufficient medium flow?
‣
Create medium flow.
No electrolyte in the measuring
chamber?
‣
Refill or replace electrolyte.
Buildup on the membrane cap?
‣
Clean sensor carefully.
Displayed value too high Polarization ended?
‣
Wait for polarization time to elapse
Is sensor calibrated/adjusted?
‣
Recalibrate/readjust.
 When calibrating, enter the current
air pressure at the transmitter.
Displayed temperature clearly
too low?
‣
Test sensor, if necessary contact the
Hauser sales team.
Membrane visibly stretched?
‣
Replace membrane cap.
Is electrolyte contaminated?
‣
Replace electrolyte.
Is working electrode coated?
‣
Clean working electrode.
Internal body defective?
‣
Change the internal body.
Anode coating worn off? Is the
anode silver instead of brown?
‣
Send sensor in for re-coating.
Displayed value too low Polarization ended?
‣
Wait for polarization time to elapse
Is sensor calibrated/adjusted?
‣
Recalibrate/readjust.
 When calibrating, enter the current
air pressure at the transmitter.
Insufficient medium flow?
‣
Create medium flow.
Displayed temperature clearly
too high?
‣
Test sensor, if necessary contact the
Hauser sales team.
Is electrolyte contaminated?
‣
Replace electrolyte.