Dwyer 8600 - Manual (Page 31)

December, 1998 Page 31 949-1277-3
ALARM TYPE AND ACTION (if present)
Caution: In any critical application where failure could
cause expensive product loss or endanger personal
safety, a redundant limit controller is required.
When setting an alarm value for an absolute alarm (A#t = AbS), simply set
the value at which the alarm is to occur.
When setting the alarm value for a deviation alarm (A#t = dE), set the
difference in value from the Set Point (SP) desired. For example if a low
alarm is required to be 5 degrees below the SP, then set A#Lo to -5. If a high
alarm is required 20 degrees above the SP, then set A#Hi to +20. If SP is
changed, the alarm will continue to hold the same relationship as originally
set.
The following diagram (below) shows the action and reset functions for both
absolute and deviation alarms.
When Alarm Power Interrupt, A#Pi, is programmed ON and Alarm Reset,
A#rE, is programmed for Hold, the alarm will automatically reset upon a
power failure and subsequent restoration if no alarm condition is present.
If Alarm Inhibit, A#iH, is selected ON, an alarm condition is suspended upon
power up until the process value passes through the alarm set point once.
Alarm inhibit can be restored as if a power up took place by pressing both
the INDEX and ENTER keys for 5 seconds.