Walchem WebMaster ONE Instruction Manual page 74

At the end of the calibration, the display will tell you if the calibration was successful or if the
calibration failed. If successful, press the Enter key after the sensor has been replaced into the
sample stream to resume control. If failed, refer to Section 8 for troubleshooting help.
The WebMasterOne will either pass or fail the calibration. Control of the oxidizer will continue
throughout this process.
If the calibration fails for any reason, refer to Section 8 for troubleshooting help.
Status
Possible status messages are; Normal (everything is OK), Sensor Error (the signal is not valid),
High Alarm, Low Alarm, Circuit Board Failure or Calibration Time. See section 8.1 for a
complete description of error messages.
Date of Last Calibration
This section is for information only, and lets you know when the last calibration occurred.
Calibration Reminder
If you want to be reminded when the electrode needs calibration, for example every 30 days then
type the desired number of days between calibration in the text box. A value of zero means you
will never be reminded. The highest value allowed is 365 days.
Self Test
The Self Test is used to check the circuitry of the sensor input. Click on the "Self Test" button, and
the controller will display either Pass or Fail, and also readings of a simulated oxidizer sensor. If
the controller passes self test, and you are having problems reading the correct value or calibrating,
then the problem must be with the sensor, wiring or installation.
mV
Displays the mV signal from the sensor in the current sample prior to calibration or conversion
into ppm. This is useful for troubleshooting.
Calculated Slope
This displays the slope (mV output of the sensor per ppm of oxidizer) of the sensor as of the last
calibration. A perfect sensor will have a slope of 100 (except it's 1.00 mv/ppm for the PAA
sensor). This is helpful for troubleshooting, and also to predict when the electrode may need to be
replaced.
Calculated Offset
This displays the mV offset of the sensor at 0 ppm (0 mV) as of the last zero calibration. The
offset information is helpful for troubleshooting.
High-High Alarm Limit
Type in the text box the sensor process value above which you a want a high-high alarm to occur.
High Alarm Limit
Type in the text box the sensor process value above which you a want a high alarm to occur.
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