> I have an alarm PV which needs no acknowledgement and is
configured with an input count filter:
> $ALARMCOUNTFILTER 3 8
> The alarm PV changes from "in alarm" to "out of alarm"
once/second for a long time.
> I see the following behaviour in alh:
>
> 6 seconds after the alarm starts toggling, the PV goes into alarm.
> After another 6 seconds, the PV goes out of alarm.
The behaviour is as intended, if the PV changes once per second its state.
Because you've specified the filter "3 8":
it goes in the alarm state, if the alarm either stays for 8 seconds,
or if it enters an alarm state three times within 8 seconds.
This PV enters an alarm state every two seconds, so after six seconds it raised an alarm the third time.
If you would change the filter to for example
$ALARMCOUNTFILTER 5 8
then it would never go into alarm (if the PV sticks to its behaviour).
When it would stop toggling and stays instead into alarm, an alarm would be raised after 8 seconds.
If it would change its state more frequent, an alarm would be raised as well.
I hope that helps to clarify the ALARMCOUNTFILTER.
Cheers from Switzerland :-)
Andreas
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