Walchem WebMaster ONE Instruction Manual page 66

Primary Sensor Assignment
This menu only appears if the Redundant Sensor Setting is Backup.
Use the pulldown arrow to select the sensor to use as the primary control sensor. All sensors of the
same type as the backup sensor will appear in the pulldown list.
Deviation from Primary Sensor
This menu only appears if the Redundant Sensor Setting is Backup.
Type the maximum allowable difference between the two sensor readings. If this deviation is
exceeded, then control of any outputs using the sensor will stop and an alarm activated.
Current Reading/Perform Calibration
The current reading is a live reading of the calibrated pH of the sample.
To Calibrate the pH electrode click on the "Perform Calibration" button and a new window will
appear. Select 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 pH control will be suspended during the calibration. Click on
"Continue" to start the calibration, or "Cancel" to abort the calibration.
If no temperature element is detected, then the controller will allow you to enter the buffer
temperature manually. Otherwise it will display the electrode temperature.
You then be prompted to "Please Rinse the Electrode". Do so, and then click "Continue".
You will now be prompted to type in the value of the first buffer being used. Do so, and 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, and then click "Continue".
You will now be prompted to type in the value of the second buffer being used. Do so, and then
click "Continue".
You will now see the mV output from the electrode. When this value is stable, click "Continue".
The WebMasterONE will either pass or fail the calibration, and prompt you to return the electrode
to the process. Click "Continue" when you are ready for pH control to resume.
If the calibration fails for any reason, refer to Section 8 for troubleshooting help.
1 Point Calibration
First you will see a warning that pH control will be suspended during the calibration. Click on
"Continue" to start the calibration, or "Cancel" to abort the calibration.
If no temperature element is detected, then the controller will allow you to enter the buffer
temperature manually. Otherwise it will display the electrode temperature.
62