Re: Alarm trigger for persistent values?

[Ralph Lange <Ralph.Lange@bessy.de>]

Hello Bernhard,

If you use the Alarm Handler (ALH) to display your alarms, there is a 
configuration option that allows you to have an alarm appear only after 
it occurred for a certain number of times or persisted for a certain time.
Look for chapter 6.3.12 or "Alarm Count Filter" in the Alarm Handler 
User's Guide.

If you want to solve this within the database, use Pete's approach, but 
rather use a calcout record and use the OCAL field (or a second calc 
record) to write the RAWTEMP value to the final ai, else you will end up 
showing the counter instead of the temperature.
I would separate the time counting from forwarding the value, which also 
doesn't link the update period of your final TEMPERATURE ai to the time 
counter resolution. So I would do something like

record (ai, "RAWTEMP")
{
	...
	field (SCAN, "I/O Intr")
	field (FLNK, "CALCFORWARD")
}

record (calc, "CALCFORWARD")
{
	field (CALC, "A")
	field (INPA, "RAWTEMP NPP MS")
	field (INPB, "CALCULATION NPP MS")
	field (FLNK, "TEMPERATURE")
}

record (calc, "CALCULATION")
{
	field (SCAN, "1 second")
	field (CALC, "(B>C||B<D)?(A+1):0")
	field (INPA, "CALCULATION.VAL")
	field (INPB, "RAWTEMP")
	field (INPC, "RAWTEMP.HIHI")
	field (INPD, "RAWTEMP.LOLO")
	field (HIHI, "60")
	field (HHSV, "MAJOR")
	field (FLNK, "CALCFORWARD")
}

record (ai, "TEMPERATURE")
{
	field (INP, "CALCFORWARD NPP MS")
}

(Code is not tested and may contain more bugs ...)

Hope this helps,
Ralph


Bernhard Lopez wrote:
> Hi,
>
> At our infrastructure monitoring system we have the case that
> some temperature values should trigger an alarm only if they
> remain above/below a threshold (HIHI/LOLO) for longer than a
> defined amount of time.
>
> As we could not find support for this feature in the documentation,
> we would be glad to receive a suggestion regarding a solution or
> implementation we could go for.
>
> The involved sensor devices are represented by "ai" records
> with a home-made device implementation. We use EPICS release
> 3.14 on Linux.
>
> Many thanks in advance!
>
> Bernhard.