Re: Alarm for noisy readback channel

[Paul Sichta <psichta@pppl.gov>]

Paul,
If you are using ALH to alarm then use the ALARMCOUNTFILTER option I
think that is it) which would suppress the ALH notification for
settable time or count-within-a-time.  Otherwise I think an AO record
has a rate-limit setting which might be used as a filter.  Your second
CALC option would work.

-ps

On Wed, Feb 22, 2012 at 17:25, Paul Nord <Paul.Nord@valpo.edu> wrote:
> I've got a network device that's misbehaving.  It "sometimes" reports an absolutely ridiculous value.  I'd like to set an alarm on this PV but I don't want the alarm sounding once or twice an hour when there's not really anything wrong.  (Never cry wolf.)
>
> In the typical failure mode it reports a "crazy" value once and then goes back to the normal value.  (The device actually returns the voltage value for a channel when you ask for a current.  And it formats a reply and happily returns "Current: 3600 A", which would be impressive for a supply running at 3600 V.  It works out to 13 MegaWatts.  The real current is just ~100 uA.)
>
> What's the best way to deal with this?
>        A CALC pv that takes this value as an input but returns zero if the reading was outside of some range?
>        A CALC pv that counts the number of readings which are outside of the proper range?  (e.g. A>1.0?(VAL+1):0 )
>
> Are there other good mechanisms?
>
> Paul
>
>
> record(ai, "$(SYSTEM):measurement_current_$(SLOT)$(ID)")
> {
>  field(DTYP, "Snmp")
>  field(SCAN, ".5 second")
>  field(PREC, "6")
>  field(EGU,  "")
>  field(INP,  "@$(HOST) pwd WIENER-CRATE-MIB::outputMeasurementCurrent.$(SLOT)$(ID) Float: 100")
>  field(ADEL, "1")
> }
>
>