Experimental Physics and
Industrial Control System

Nick Rees <[email protected]> · Thu, 3 Feb 2000 08:26:02 -1000 (HST)

On Thu, 3 Feb 2000, Deb Kerstiens wrote:

> I don't like to have to process the output records and cause any resulting 
> processing just to get the current value of an output record after a reboot, 
> so it would be great to add the selectable readback to all output records
> or add something like RINI (read at initialization) to read but not process.

While we are on the subject (which has diverged somewhat from the original
one), I have often had the similar problem caused by rebooting fieldbus
modules but not the IOC. In this case I have occasionally wanted my output
record to readback the new value (post-reboot) from the fieldbus module,
rather than set it to the last EPICS value. Hence I have always felt there
was a better way of handling this re-initialization of output records.

I have also found the treatment of all these things a bit inconsistent -
especially as the code resides in device, rather than record, support (and
so is developed by a greater number of programmers). One thought I had was
to support a read routine in device support of output records, and then
move a bit of the logic back into the record. We could also support a
callback when the output hardware re-inialises. I admit that this is
difficult to make backwards compatible.

Just a few thoughts to create a few more ideas. I must admit I only
scanned Andrew's new link notes, so I can't remember how much of this is
addressed by his ideas.

Cheers

Nick Rees

Joint Astronomy Centre               Ph:       +1 (808) 961-3756
660 N. Aohoku Place                  Fax:      +1 (808) 961-6516
Hilo, HI.  96720                     Internet: [email protected]

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System