Motor Operated Valve
Motor Operated Valve
(OP)
Does anyone have any suggestions on how to show MOV controls on the P&ID diagram using ISA standards. For instance an MOV that is opened and closed with discrete signals from a PLC and has limit switches for position indication also connected to the PLC inputs.





RE: Motor Operated Valve
RE: Motor Operated Valve
If it's operated by PLC or DCS or operator, depends the symbol you use "around" the tagname
(sorry for my English, I've never been good in prepositions)
Cheers
RE: Motor Operated Valve
The limit switches ZSC/ZSO is acceptable under ISA. I have never seen ZSH/ZSL (high and low for a linear valve I suspect) in my industry.
If the valve is used for on/off, it usually takes a XV or UV tag name. If the valve is used for regulatory control application, then they would take the normal PV, FV, TV type of designation. I have also seen HV for operator control only valves.
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RE: Motor Operated Valve
RE: Motor Operated Valve
I checked API RP 14C to see if it has the ZSO and ZSC. API regards the S for safety instead of switch. A check valve is tagged FSV - flow safety valve. Regardless, "ZS" was not found in a word search of API RP 14C or other codes and standards.
RE: Motor Operated Valve
I guess we disagree. That's okay.
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?
RE: Motor Operated Valve
At several companies where I've worked, it's been ZSO and ZSC for the position switches.
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