Craig –
You need to have interlock/PLC signal power and motor operator power separate. We deenergize and lock out the MOV’s at a breaker panel on the structure to protect the open drum from receiving hydrocarbon inadvertently.
I would also recommend not doing a sequence based interlock logic, if that is what you are inferring. I recommend that each valve have a unique relationship with 2 or 3 other valve positions; those valves must be in their proper postion (closed, open, not closed or not open) as a permissive for moving the given valve to the desired position.
Best regards – Mitch
