Walchem WebMaster ONE Instruction Manual page 99

Current Reading
This is a display of the current process value as measured by the assigned sensor.
Status
This displays the current status of the relay output, either "Off" or "On", and if on, the amount of
time it has been on. Possible status messages are Off, Off/Manual, On/Time counting
down/Sampling, Off/Time counting down/Holding, On/Time counting down/Blowdown, Off/Time
counting down/Waiting and On/Time counting down/Hand (for manual activation). The only
possible error messages are Interlock and Sensor Error. See section 8.1 for a complete description
of error messages.
Custom Name
This menu allows you to call the output another name if desired. Type the new name in the text
box.
Set Point
Type in the desired set point value. The control direction is always Force Lower.
Interval Time
Type in the desired time between samples. Too short a time will waste water and drop the
conductivity well below the set point. Too long a time will cause the conductivity to rise too high,
potentially resulting in scale or carryover.
Duration of Sample
Type in the desired sample time. This should be as short as possible while still guarantying a fresh
sample of boiler water at the electrode.
Hold Time
Type in the desired time to hold the water sample while it returns to boiler pressure.
Blowdown Time
Type in the desired maximum time to blowdown if the conductivity is above the set point. Too
long a time will waste water and drop the conductivity well below the set point. Too short a time
could cause the conductivity to rise too high, potentially resulting in scale or carryover.
Proportional Band
Type in the conductivity above the set point that will correlate to the maximum blowdown time.
For example, the set point is 2000 S/cm, the proportional band is 100 S/cm, and the maximum
blowdown time is 30 minutes. If the conductivity measured is 2100 S/cm or above, the valve
opens for 30 minutes. If the conductivity measured is 2050 S/cm, the valve opens for 15 minutes.
If the conductivity measured is 2000 S/cm or below, the valve remains closed and the Interval
time counts down.
Mutual Interlocks
Click the check boxes to select or de-select the relays and analog output control outputs that you
want to be prevented from turning ON if this output relay is already ON. If you do not need any
other output to shut off when this relay turns on, UNCHECK all boxes. The selection is mutually
95