The MODEL 420 is a proportional speed controller for 12 volt DC solenoid-operated AODD pumps. It translates a 4 to 20 milliamp signal into a pump speed. It can operate from stop to 499 strokes per minute and use 4 milliamps or higher as either its low or high speed and 20 milliamps as the other speed and it interpolates all speeds in between.  The controller has a toggle switch to run the unit in either the 4-20 ma mode or "Jog" mode which runs the pump without speed variation for priming etc.

The controller can be operated from its panel or remotely via dry contacts. The display keeps you informed about the milliamp signal value and the pumps current speed.