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For input types using automatic temperature compensation, the temperature reading will be displayed until the reading
is stable and then move to the next step without any action required.
If successful, the calibration gain or offset will be displayed. Click Save to accept the new value or Cancel to retain the
previous calibration.
If the new value results in a gain or offset that is out of the allowable range for the input, Calibration Failed will be
displayed. Click OK to end the calibration and retain the previous calibration settings. Refer to section 8.1 Calibration
Failure for help troubleshooting each type of sensor.
7.0 MAINTENANCE
The controller itself requires very little maintenance. Wipe with a damp cloth. Do not spray down the controller unless
the enclosure door is closed and latched.
7.1
Electrode Cleaning
NOTE: The controller must be recalibrated after cleaning the electrode.
Frequency
The electrode should be cleaned periodically. The frequency required will vary by installation. In a new installa
tion, it is recommended that the electrode be cleaned after two weeks of service. To determine how often the elec
trode must be cleaned, follow the procedure below.
1. Read and record the conductivity.
2. Remove, clean and replace the conductivity electrode.
3. Read conductivity and compare with the reading in step 1 above.
If the variance in readings is greater than 5%, increase the frequency of electrode cleaning. If there is less than 5%
change in the reading, the electrode was not dirty and can be cleaned less often.
Cleaning Procedure
The electrode can normally be cleaned using a cloth or paper towel and a mild detergent. If coated with scale,
clean with a dilute (5%) solution of hydrochloric acid solution. Occasionally an electrode may become coated
with various substances that require a more vigorous cleaning procedure. Usually the coating will be visible, but
not always. To clean a coated electrode, use fine grit abrasive, such as emery paper. Lay the paper on a flat surface
and move the electrode in a back and forth motion. The electrode should be cleaned parallel to the carbon elec
trodes, not perpendicular.
Clean in this
direction
Figure 21 Cleaning the Electrode
