I work at a facility where I am the sole maintainer of a new DeltaV (14.3.1) system.
I'm working through creating some new logic for one of our systems and I'm trying to come up with some philosophical guidelines that I will use going forward for uniformity. One thing that I struggle with a bit is what the purpose of "RCAS" and "ROUT" is. Coming from other systems, I take RCAS/ROUT to indicate that a loop is being controlled by something "supervisory" rather than simply being commanded by another loop via the standard Cascade approach (parent loop and a child loop).
I have some discrete valves (open/closed) that I intend to operate in a sequence, and I want to take control of those valves and indicate to the operator that supervisory controls are in command. In my mind, I would simply place these discrete valves in RCAS and set the SP of the valve according to what I want it to do.
However, I've come to realize that EDC blocks do not appear to allow RCAS, and the documentation supports that finding by specifying explicitly that only AUTO and CAS are valid modes. Can someone help me understand why this is the case? Is there something that I am missing that will allow me to put these discrete devices into RCAS? What do you recommend as the intuitive approach to what I'm trying to do? Just use CAS instead?