Current ‐ to ‐ Pressure Converter
The Woodward Current to Pressure Converter (CPC) is designed for positioning steam and fuel valves and/or the associated servos. A 4–20 mA in/out signal is linearly and proportionally converted into a hydraulic output pressure. The CPC can thus interface with any electronic control, such as Woodward MicroNet™ systems and the Woodward 505 Control. It connects to pressure-operated servo systems and to single-acting power cylinders. The CPC is suited for new as well as retrofit applications.
The CPC is an electrohydraulic, pressure-regulating valve, which consists of a valve, an actuator, a pressure sensor, and on-board electronics.
The electronics perform the signal conditioning by comparing the actual output pressure with the command, which results in a reference signal for the valve position. This reference signal is then compared with the actual position, resulting in a drive signal. The driver circuit then outputs the appropriate signal to the actuator, which positions the hydraulic valve to the required position.
The valve consists of two ports; one from supply to output, and one from output to tank. By opening one of these ports, the output pressure decreases or increases.
Two output signals are provided: a 4–20 mA signal, representing the actual output pressure, and a relay output, indicating a malfunction of the CPC.