Electric actuator for fluid control valves

An electric actuator for operating a fluid control valve and controlling the operation of a plurality of field instruments having an associated fluid control valve, said electric actuator comprising:

• a drive unit having an output for coupling to said fluid control valve for opening and closing the valve;
• an electric motor coupled to the drive unit for driving the drive unit in response to open and close power levels;
• a control unit coupled to a power source and supplying said open and close power levels to the electric motor for opening and closing the valve;
• said control unit including auxiliary control means for responding to an initiation signal and providing auxiliary control power levels to said plurality of field instruments to control the operation of said field instruments in the opening and closing of said associated fluid control valve;
• said auxiliary control means includes auxiliary control output lines for connection to said plurality of field instruments to provide auxiliary control open and close power levels to a selected field instrument to control the opening and closing travel of a fluid control valve associated with said selected field instrument;
• and
• said auxiliary control means further includes auxiliary monitoring means for monitoring the fully closed and fully open state of each of the valves associated with each of said field instruments and providing a respective signal indication thereof to said auxiliary control means, and a respective pair of auxiliary travel input lines for connection to said plurality of field instruments for respectively monitoring and coupling said fully closed and fully open state of each of said associated valves to said auxiliary monitoring means and to discontinue said auxiliary control open and close power levels to respective ones of said field instruments upon sensing the fully closed or fully open state of said associated valve has been reached.