Instruction manual

57
% Difference from theoretical
This displays the % difference of the slope from the theoretical value as of the last calibration. The
higher this percentage, the weaker the pH electrode. The calibration will fail if this percentage
exceeds 80%. This number is the most useful to determine how much life is left in the electrode.
Self Test
The Self Test is used to check the circuitry of the pH input. Click on the “Self Test” button, and
the controller will display either Pass or Fail, and also readings of a simulated pH and temperature.
If the controller passes self test, and you are having problems reading the correct pH or calibrating,
then the problem must be with the electrode, wiring or installation.
High Alarm Limit
Type in the text box the pH value above which a high pH alarm will be activated. Any value
between –2 and 16 is acceptable.
Low Alarm Limit
Type in the text box the pH value below which a low pH alarm will be activated. Any value
between –2 and 16 is acceptable.
Click on the “Submit” button to save the changes.
6.9 ORP Input Menu (only appears if ORP option card is installed)
Current Reading/Calibrate
The current reading is a live reading of the calibrated ORP of the sample.
To Calibrate the ORP electrode click on the “Perform Calibration” button and a new window will
appear. Select either a 2-point calibration, a 1-point calibration or a 1-point process calibration by
clicking the appropriate button.
2 Point Calibration
First you will see a warning that ORP control will be suspended during the calibration. Click on
“Continue” to start the calibration, or “Cancel” to abort the calibration.
You then be prompted to “Please Rinse the Electrode”. Do so, then click “Continue”.
You will now be prompted to type in the value of the first standard solution being used. Do so,
then click “Continue”.
You will now see the mV output from the electrode. When this value is stable, click “Continue”.
You then be prompted to “Please Rinse the Electrode”. Do so, then click “Continue”.
You will now be prompted to type in the value of the second buffer being used. Do so, then click
“Continue”.
You will now see the mV output from the electrode. When this value is stable, click “Continue”.
The WEBMASTER will either pass or fail the calibration, and prompt you to return the electrode
to the process. Click “Continue” when you are ready for ORP control to resume.
If the calibration fails for any reason, refer to Section 8 for troubleshooting help.