Re: calc record question

[Marty Kraimer <mrk@aps.anl.gov>]

Maren Purves wrote:

> Hi all,
>
> I need/partly have the following application:
>
> An IOC provides a (floating point, if that matters) number that
> depends on something in this IOC to another IOC where it needs
> to be added into a calc record. We do this in other places, and
> in itself it isn't a problem. The question I have is:
>
> What happens if the first IOC is switched off?
> (The number it contributes should be switched to 0.0 before it
> is turned off. This IOC may be switched off for months at a
> time.)
>
> Will the calc record treat the non-existing input as a 0?
> Will it also do so when it is rebooted?
>
> Thanks,
>
> Maren
> (trying to avoid putting in a switch)



The calc record will continue to use the value it last obtained or 0.0 
if it never got a value from the other ioc. If you specify MS on the 
link the calc record will go into alarm if the other IOC is down.

Here is a way to do what you require. Create the following two 
additional records

record(ai,"<actualLink>") {
   field(INP,"<pvInOtherIOC> CP MS")
}
record(calc,"<checkStatus>") {
   field(INPA,"<actualLink> ")
   field(INPB,"<actualLink>.SEVR")
    #SEVR=3 means INVALID_ALARM
   field(CALC,"(B=3)?0.0:A")  
}


Than have your original calc record link to <checkStatus> instead of 
<pvInOtherIOC>, e.g.
   field(INP<X>,"<checkStatus> PP")

Perhaps someone can think of a more clever way that does not require two 
additional records.

Marty Kraimer