Experimental Physics and
Industrial Control System

Luedeke Andreas <[email protected]> · Mon, 16 Aug 1999 09:56:17 +0200

Hi Andrew,
yes, that link support would be exactly what I would like to have.
It even would solve a few problems I had and didn't bother to ask.
I'm looking forward to this new release 8-) and meanwhile I will handle 
the dynamic INP/OUT evaluation by myself :-(

- Andreas

Andrew Johnson wrote:
> 
> Hi Andreas,
> 
> you hit one of my subject areas again...
> 
> Luedeke Andreas wrote:
> >
> > I'm writing a driver for a serial IP module (in-house) with
> > a VME_IO type of the INP and OUT field string:
> > #Cn Sm @parameter
> >
> > I want to allow dynamical changes of n, m and parameter.
> > Do I have to make a copy of n, m & parameter and compare it
> > to identify changes or is there a kind of flag that the field has changed?
> 
> With current versions of EPICS yes you have to keep track of the link
> fields yourself if you want to support dynamic changes.  Very few device
> support routines do this yet as the ability to change links at run-time
> was only introduced in EPICS R3.13
> 
> > I think it is possible to have a special processing in record support if
> > a field has changed. That would be the most elegant way to my opinion.
> > But my driver will support roughly a dozen types of records and I don't
> > want to rewrite them all.
> 
> I made a proposal at the last EPICS collaboration meeting to change the
> code that handles links to make them much more generic, and one of my
> changes will be to allow the device support to give a routine to be called
> when the link is changed.  This will be implemented (hopefully in the next
> major EPICS release), but I haven't had a chance to start looking at the
> code yet.  When this is released you'll have to make some minor changes to
> your code, but you'll also be able to define your own link formats.
> There's a document describing the proposal at
>         http://www.aps.anl.gov/asd/people/anj/lnkSup.html
> 
> - Andrew
> --
> I brake for tail-gaters

-- 
Andreas Luedeke, Controls Group, Swiss-Light-Source, PSI
mailto:[email protected], tel:+41-(0)56-310-4002, fax:-4413

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System