Abstract: A control valve or system of control valves governs fluid flow by digitally comparing a feedback signal from a fluid control loop with a command signal corresponding to a desired flow rate in a high pressure operating fluid flow line. In the preferred embodiment, a control valve system, such as a pressure relief valve, is operated under the control of a digital computer. The pressure relief valve is operated at a control pressure to regulate flow in an operating hydraulic system. The control pressure chamber is coupled to a relief line through a control pressure reduction valve and to a control pressure enhancement valve which is in communication with the operating line of fluid flow. A feedback signal indicating actual control pressure, flow rate or load position is compared with a command control pressure, flow rate or position. Preferably, the results of several comparisons are averaged together to provide an error correction signal.