Alarms and Alarm Latching
Alarm latching lets you latch a counter alarm once the alarm is triggered. The alarm
remains set even if the condition that triggered the alarm disappears, until the alarm
is unlatched.
Alarm latching is available on a per counter basis. You can latch the following
alarms:
- Missing Pulse Alarm
- Zero Frequency Alarm
- Zero Frequency Average Alarm
- Frequency Alarm
- Frequency Average Alarm
- Pulse Width Alarm
- Pulse Width Average Alarm
- Acceleration Alarm
- Acceleration Average Alarm
- Deceleration Alarm
- Deceleration Average Alarm
For the Missing Pulse and Zero Frequency alarms, you must enable latching using the
module tags. Latching is always enabled for other alarms.
Enable Latching
You can enable alarm latching in Module Properties. Go to the Counterxx → Alarms
view.
Unlatch Alarms
IMPORTANT:
Before you unlatch an alarm, make sure that
the condition that triggered the alarm is no longer exists.
Once an alarm is latched, you must use a rising edge of its unlatch tag in the output
tags to unlatch the alarm. The alarm type determines which module tag you must
change.
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