Experimental Physics and
Industrial Control System

Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov> · Thu, 15 Apr 2021 13:47:29 -0700

On 4/13/21 11:29 PM, Ru Igarashi via Tech-talk wrote:
> [normally, I'd inline my response but I'm stuck with Web Outlook.  My apologies.]
> 
> Hello Andrew,
> 
> re: camonitor: the errant sequence is the same with and without camonitor
> running in parallel.  My thinking was that the reliance on the Channel
> Access monitors meant that update occasionally necessarily would
> eventually be out of sync. ...

I don't think anyone else addressed this point specifically,
and I think it is an important point to make.  CA (and PVA)
subscriptions should always, eventually, be "in-sync". This is an
essential property for a robust distributed control system to have!

If a PV produces a burst of updates which exceeds some internal
buffers, the most recent update will never be discarded.  So all
clients will eventually receive the most recent update produced.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System