Experimental Physics and
Industrial Control System

Ben Franksen via Tech-talk <tech-talk at aps.anl.gov> · Mon, 15 Mar 2021 08:52:26 +0100

Am 14.03.21 um 21:56 schrieb Manoussakis, Adamandios:
> I was able to get it to compile and it seems to be working now.  I
> think there may have been another compilation error somewhere after
> retyping it out from scratch.  I still need to understand more about
> the section on when to use monitor vs.  explicit pvget().  

monitor is for when you want your program to automatically receive
updates about a PV and then act on that by re-evaluating the when
conditions (which may in turn cause a state change).

pvGet is for when you need a snapshot of some PV as input for a
calculation, but the result doesn't influence a state change decision.

There is a certain overlap in that most uses of pvGet can be replaced
with placing a monitor on the PV and then just using the variable. It's
partly a matter of taste and partly a matter of efficiency (monitors are
slightly more expensive).

> I assume
> the when() block only runs once when a state transition happens is
> that correct?

Yes.

Cheers
Ben
-- 
I would rather have questions that cannot be answered, than answers that
cannot be questioned.  -- Richard Feynman

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System