Re: How to tag soft channels as undefined/disconnected

[Kellee Summers <ksummers@lbto.org>]

This sounds pretty simple and what I'm trying to do.  The problem is I 
don't know how to do this part:  "sets the PV invalid"
How do you do that?  Is that just some kind of timeout on the processing?

Thanks for your help,
Kellee

On 08/13/2014 06:47 AM, Lionberger, Carl A. wrote:
> For a project where I had a python program updating soft PVs, I wrote a timeout device support to use instead of the soft channel device support.  It times out and sets the PV invalid if a new value was not put to it within the timeout period since the last put. The C++ application just wouldn't put the value to the PV if the instrument data was invalid, and then the PV would go invalid without further action.  When valid data became available, the application would put it to the PV and the PV status would go normal again.
>
> Carl
>
> Carl Lionberger
> Instrument Data Acquisition and Controls
> Spallation Neutron Source
> ________________________________________
> From: tech-talk-bounces@aps.anl.gov <tech-talk-bounces@aps.anl.gov> on behalf of Kellee Summers <ksummers@lbto.org>
> Sent: Tuesday, August 12, 2014 7:02 PM
> To: tech-talk@aps.anl.gov
> Subject: How to tag soft channels as undefined/disconnected
>
> Hi All,
>
> We have set up an EPICS R3.14.12.4 database of pure software channels
> (on a Linux system) so that we can use the alarm handler. The channel
> values are being driven by a C++ software application that reads our
> instrument data.   When the instrument data is stale (determined by an
> out-of-date timestamp), I would like to
> set the channels to UDF so that the alarm state is INVALID.
>
> The SEVR and STAT alarm fields are non-modifiable.  I tried setting the
> UDF field but it didn't give me a disconnected channel.
>
> Do I need to modify the record processing?
>
> Suggestions?
>
> Thanks