Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Tue, 27 Mar 2007 17:47:41 -0500

Hi Emmanuel,
Emmanuel Mayssat wrote:

On Tue, 2007-03-27 at 14:10 -0500, Ned D. Arnold wrote:
A better solution might be to use Channel Access security rules such
that writes to GAIN are not allowed when RUNNING. This stops CA from
writing to VAL and EDM should show you that writing is disallowed.

What are you referring to here? The DISP field?

If you've never heard of Channel Access security rules I suggest you sit
down with Chapter 8 (Access Security) of the IOC Application Developers'
Guide sometime. They have nothing to do with the DISP field.
I just remembered that there is a permissive record in the record
manual. What are the typical application for such a record?

http://www.aps.anl.gov/epics/wiki/index.php/RRM_3-13_Permissive

The Permissive record was designed to facilitate interlocked
communication between two programs. It has not been converted to R3.14
to my knowledge, and I'm not aware of anyone who is actually using it.
There have been at least a couple more recent records designed for
vaguely similar activities such as the APS runControl record and the
CAD/CAR/SIR records from Gemini and Observatory Sciences.
- Andrew
--
The right to be heard does not automatically include
the right to be taken seriously. -- Hubert H. Humphrey

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System