The Ringway Spropdrv proportional valve driver card has been designed to interface directly between a PLC 4-20mA output card and a hydraulic proportional control valve. The card is mounted in a rack that can accommodate two cards. If more cards are required for an installation larger racks can be supplied. The card requires a separate power supply of 16 to 24V dc or 13 to 24V ac capable of delivering enough current to drive the connected valve/s. The card will produce a current flow in a connected valve that is proportional to the controlling PLC signal applied to it. The electronic control method employed is a 300Hz switch mode regulator with active current feedback. This method ensures high-speed response and efficiency with little variation due to heat or other variables.

The output span for a given control signal can be adjusted from the front edge of the card using the span trim pot.