Assumend that MOV is the acronym of Motor Operated Valve and ROV means Remote Operated Valve.
While ROV ia s generic term used to indicate an actuated (pneumatic, electric, hydraulic or other) valve which may be opened or closed from a distance by means of electric signal, MOV indicates a valve specifically actuaded by a motor actuator, usually electric.
So a ROV can be MOV.
As far as I know, there is no standard for acronyms axcept ANSI/ISA 5.1. so this case is considered an Industrial Standard.
ISA says:
2.8.2 Symbols different from those given in this standard and User’s choice letters when used, shall be fully described and detailed in the User/Owner’s standards, guidelines, or specifications and in drawing cover sheet legends and notes.
I agree with the above, but be careful when doing this subsea as ROV can also mean Remotely Operated Vehicle and an ROV valve could mean a manual valve which needs an ROV to go and mate with it turn the actuator to open / close it....
context is everything.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
In addition, an MOV (electric motor operated valve) cannot enable a failsafe position; it is always fail last position. A spring loaded ROV can be configured to be failsafe if required.
