Hi,
I have to make logic were one PID loop controls two series-connected valves (look File 2). In logic, PID SP is temperature what comes from dynamical graph (depend on the external air temp), PV is outgoing temperature (after valves), PID CV is used to activate PLC relay outputs- OPEN, CLOSE (look File 1) There is no feedback from valves, from technical data is known that OPEN position to CLOSE position takes 150 sec (both valves are same type).
Actions:
1. If its needed to raise water temperature, then its activated OPEN output, which is linked to valve "Direct" (look File 2, 11GM