Endress+Hauser CM14 - ORP Sensors

Calibration and adjustment CM14
24
The calibration is not completed successfully or is canceled and is not valid.
Possible reasons:
• The sensor is old or contaminated. As a result, the permitted limit values for the slope and/
or zero point are exceeded.
– Clean the sensor
– Regenerate or replace the sensor
• The measured value or temperature is not stable. As a result, the stability criterion is not met.
– Keep the temperature constant during calibration.
– Replace the buffer.
– The sensor is old or contaminated. Clean or regenerate.
To calibrate the sensor, you can also remove it from the medium and calibrate it in the
laboratory. Since Memosens sensors save the data, you can always work with
"precalibrated" sensors and do not have to stop monitoring the process to perform a
calibration.
7.3 ORP sensors
7.3.1 Single-point calibration
The buffers contain ORP pairs with a high exchange current density. Such buffers have the
advantage of higher accuracy levels, better reproducibility and faster measurement response
times.
Temperature compensation does not take place when measuring the ORP since the thermal
behavior of the medium is not known. The temperature is indicated with the measurement result,
however.
With this type of calibration, you work with calibration buffers, e.g. ORP buffers from Endress
+Hauser.
Calibration of an ORP sensor
1. Press "E" to call up the main menu.
2. Press the "+" button to navigate to the "Calibration" menu.
3. Press "E" to open the menu.
Ã
Display reads "mV (act)".
4. Remove the ORP electrode from the measurement medium, flush with distilled water, dry
it and immerse it in the ORP buffer.
5. Press "+".
Ã
Display reads "Insert sensor in med.".
6. Press "+".
Ã
Display reads "wait for stable value".
7. The current status of the ORP buffer appears on the display.
8. Press "+".
Ã
Display reads "Save Calib. Data?"
9. Press "E" and select "yes" to confirm.