Dwyer Valve PositionerThe Series VPT Valve Position Transmitter from the Proximity Controls Division of Dwyer Instruments Inc. allows for the monitoring of linear or rotary valve position with a 4–20 mA output signal. Using a resistance gear in conjunction with a potentiometer, the change in resistance outputs a proportional current signal, which is sent to the controller. The standard LCD display allows the operator to monitor the precise position of the valve. The Series VPT has a lightweight (1.3 lb (.6kg)) aluminum construction. – dwyer-inst.com