Walchem W600 Series Instruction Manual page 56

While a Total Alarm is active, the linked pump will be controlled based on the Total Alarm Mode setting:
Interlock
Maintain
Flow Verify Alarm
The W600 monitors the status or current percent output of the channel linked to the feed monitor to determine if a
Flow Verify alarm should be activated.
The Flow Alarm Delay setting (MM:SS) contains the time to trigger the alarm if the output is activated and no
pulses are registered. To avoid nuisance alarms at very low flow rates, if the linked output is a solid state relay (set
with a pulse proportional or PID control mode) or an analog 4-20 mA output, the alarm will only be activated if
no input pulses are monitored while the output is set to greater than a specified Dead Band (%).
The Flow Alarm Clear setting is the number of pulses that must be registered to verify that pump operation is
restored and clear the Flow Verify alarm. During Flow Verify alarm conditions, the count of pulses registered will
be reset to zero if no single pulses occur during the Flow Alarm Delay time period. In this manner, random single
pulses spread over a long time period will not accumulate and result in a Flow Verify alarm being cleared before
product feed is actually restored.
If desired, a user can configure the feed monitor to attempt to reprime the pump when a Flow Verify alarm first is
activated.
The Reprime Time (MM:SS) specifies the amount of time that the output should be energized after the initiation of
a Flow Verify alarm. If the linked output is a solid state relay (set to a pulse proportional or PID control mode) or
an analog 4-20 mA output, the output will be set to the Max Output percent during the reprime event. If the Flow
Verify alarm is cleared during the reprime event (because the specified number of pulses was registered), the reprime
event will be immediately ended and normal control of the output channel will be restored.
While a Flow Verify alarm is active, the linked pump will be controlled based on the Flow Alarm Mode setting:
Disabled
Interlock
Maintain
If a Flow Verify alarm is active and Interlock is selected, the output to the pump will be turned off after the specified
Reprime Time and only operator actions can restore normal control operations. In most cases, action will be taken
to manually reprime the pump, refill the chemical tank, etc. and the output will be put into Hand mode to confirm
proper operation of the pump. When the Feed Monitor registers sufficient pulses, the Flow Verify alarm will clear
and the pump output can be put back into Auto Mode.
If both Total Alarm and Flow Verify alarms are active simultaneously, an Interlock selection for either mode set-
ting will take precedence for pump control. Automatic output control will continue despite the alarm conditions
only if Maintain is selected for both mode settings.
Interlocking or Activating any Control Output with a Feed Monitor Input
Digital Input channels are available for selection as Interlock Channels or Activate With Channels by any output.
If a Feed Monitor is selected in this manner, the Digital Input will trigger that action if any alarm (Flow Verify,
Total Alarm, or Range Alarm) is currently active.
Input Details
The details for this type of input include the current flow rate of chemical feed, the total volume fed since the last
reset, alarms, the status of the output linked to the input, the date and time of the last total reset, and the current
type of input setting.
Settings
Touch the Settings icon to view or change the settings related to the sensor.
Totalizer Alarm
The output will be OFF while the alarm is active.
The alarm condition has no effect on output control.
Flow Verify alarms are not monitored, no change in output control.
The output will be forced OFF while the alarm is active.(except during the reprime event)
The alarm condition has no effect on output control. (except during the reprime event)
A high limit on the total accumulated volume of chemical fed may be set, to trigger a
Total Alarm.
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