Walchem WebMaster ONE Instruction Manual page 127

Unit Volume to Trigger Output
Type in the text box the volume of solution that needs to enter the system in order to trigger the
feed.
Specific Gravity of Chemical Fed
Type in the text box the specific gravity of the product being fed.
Pump Flow Rate
Type in the text box the flow rate of the pump used to feed the product. For the best accuracy, the
flow rate should be measured using a draw down cylinder with the pump discharge into normal
system pressure.
Reset Timeout
(only appears if the Output Time Limit below has been exceeded)
There is a button called "Reset Timeout" which is used to reset the output if it has been activated
for longer than the time limit imposed in the "Output Time Limit" menu described below.
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
exclusive, meaning that if Relay 2 has Relay 4 interlocked, then R2 won't turn on if R4 is already
on, and R4 won't turn on if R2 is already on. This feature should be used with caution since it can
potentially delay a chemical addition for a long time.
Output Time Limit
Type in the text box the maximum amount of time that the relay can be continuously activated
before the controller deactivates the relay and activates an Output Time Limit alarm. This is
intended to prevent the output from running out of control if the input fails in such a way that it
will never deactivate the relay.
Note that the relay will not activate again until someone resets the timer!
It will take some experience to find out what the normal output on-time will be. If the relay cycles
open and closed under worst case conditions in 30 minutes, you may want to set the Output Time
Limit at 60 minutes.
Hand Time Limit
Type in the text box the maximum number of minutes that the relay can be activated in the Hand
mode. Any value between 1 and 1440 is acceptable.
Click on the "Submit" button to save the changes.
Output Mode
Click on the radio buttons to manually control the relay. The normal selection will be Auto, where
the controller uses the various set points to open and close the relay. You can force the relay closed
regardless of the set points by selecting Hand, or force the relay open regardless of the set points
by selecting Off.
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