A valve actuator somethimes require a lower control pressure than available from the plant control header or it requires local on/off control. This can be achieved by means of a local installed pressure regulator and/or solenoid valve, mounted against a mounting plate attached to the actuator or directly mounting against the actuator. This is usually done for low pressure pneumatic operated valves. And in some situations the actuator position must be made visual, which could be done with end switches (fully open / fully closed) or a positioner and/or visual valve position indicator
