I’m currently having an issue with analogue alarms. I have a point with a high alarm of 100 (inclusive) to infinity; Ack Mode is Manual; Send Clear is True; Alert Deadband is set to 5. What I expected to happen is an alarm will be raised when the value reaches 100, and will not clear until the value drops to 95. The following sequence of events occurs:
The value increases to >100 and an alarm comes up.
The value drops to 99 - because of the deadband no clear is sent.
The value increases again to >100. A second alarm is raised.
No clear is sent even when the value drops below the deadband.
If the value is ‘trembling’ around the alarm level, steps 2 and 3 can be repeated many times.
The result of all this is that many orphan alarms appear in the alarm list, with no way of clearing them. Any ideas?