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Watlow D4T Data Logger
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Chapter 5 Function Reference
Logic
Set which state (on or off) of the alarm function's transmitter indicates there is an alarm.
Options:
• Close on Alarm:
the alarm function's transmitter is off when there is no alarm and on
when there is an alarm.
• Open on Alarm:
the alarm function's transmitter is on when there is no alarm and off
when there is an alarm.
Delay Time
Set a length of time, in seconds, that an alarm condition must be present before the alarm
state and output are triggered. This setting determines the minimum time that the value at IN
must be continuously above the High Set Point or below the Low Set Point before the alarm
state and alarm function’s output indicate an alarm. If the value at IN returns within the nor-
mal range before this time, no alarm occurs. This feature can be used to minimize nuisance
alarms.
Range: 0 to 9,999 seconds
Low Set Point
Set the process value or temperature that triggers the low process alarm.
Range: -99,999 to 99,999
High Set Point
Set the process value or temperature that triggers the high process alarm.
Range: -99,999 to 99,999
Clear Alarm
Set this parameter to
clear
to reset the alarm state after correcting the condition that caused
the alarm.
Options: Ignore, Clear
Silence Alarm
Set this parameter to
silence alarms
to deactivate the output after the alarm occurs.
Options: Ignore, Silence Alarms
Deviation Alarm
A Deviation Alarm's transmitter becomes active when the receiver (IN) rises above CTR (cen-
ter) by more than the High Set Point or drops below CTR by more than the Low Set Point. The
alarm conditions define a deviation window relative to CTR. CTR is typically connected to a
set point so that when it changes, the deviation alarm window moves with it. The alarm’s be-
havior can be further customized with Logic, Latching, Blocking, Silencing and Delay Time pa-
rameters.