Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Thu, 22 Jun 2006 10:21:29 -0500

Hi Michael,

Laznovsky, Michael wrote:

Since the snc compiler doesn't currently generate any code to protect

any part of the "action" functions (the body of each "when"), perhaps

the easiest way to go would be to add semaphores around those (only if

compiled for debug, to avoid the overhead otherwise). Any other ideas?

I don't know enough about the internal workings of the sequencer to

provide specifics, but I wonder if there is currently any protection

between a sequence action running and a CA event callback updating its

monitored variable. This would need exactly the same protection that

we're talking about for the local variable access API, so you might want

to investigate how that is done (if at all). Of course the problem here

is that single SNL program may have multiple state sets, and if you add

a mutex the tasks for each state set could end fighting for access to

the same (set of) variable(s).

- Andrew
--
Not everything that can be counted counts,
and not everything that counts can be counted.
  -- Albert Einstein

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System