SFC of a PI Controlled system

Hi people, I've got a few questions about how to draw a SFC for a PI controlled system.

The system contains a few componements.

2 pumps, (P1 & P2)
3 magnetic valves (open or close), (MA1, MA2 & MA3)
1 pressure controlled valve (from 0-100%) (PV)

and ofcourse a PLC.

We need to draw a SFC for this system. The pumps and magnetic valves are easy, but the pressure controlled valve has to be controlled by the PI controller.

I attached something I came up with, but I'm not sure if it's correct.



This way the PI controller keeps going in a loop and keeps making the calculations about the % the valve should be open and the Valve keeps going in a loop so it can execute it's function.

thanks in advance

What is "SFC" an abbreviation for? "? Function Chart?

Most of the SFC (sequential function chart) controllers have a portion of memory that is scanned continuously (some call it post-processing). This portion is the ideal location for interlocks and PID loops. The loops can be enabled by the use of memory coils in the actual SFC.