Patent ID: 7862003

Claim:
Position controller ( 5 ) in combination with a valve ( 2 ) actuating system wherein said position controller ( 5 ) is connected by a pneumatic line to a pneumatic actuator ( 1 ) of said valve, comprising: an I/P converter ( 7 ); an electric power line ( 6 ) in electrical communication with said position controller ( 5 ); said I/P converter controlling said pneumatic actuator and said valve ( 2 ); a switch device ( 10 ), said switch device includes a contact portion having switch contacts, said switch device includes an actuation portion, a data processing unit ( 9 ), said switch interposed between said data processing unit ( 9 ) and said I/P converter ( 7 ); said electric power line ( 6 ) and said data processing unit ( 9 ) control said I/P converter according to the live-zero principle; said power line ( 6 ) includes an electrical current therein; an additional circuit ( 11 ) monitors said current in said power line ( 6 ); and, said additional circuit ( 11 ) controls and actuates said actuation portion of said switch device ( 10 ) and opens said switch contacts when said current falls below a threshold current.