Abstract: An electrohydraulic system includes a plurality of electrohydraulic devices individually controlled by microprocessor-based control electronics. The device controllers are connected in common by a bidirectional serial data bus to a master controller for coordinating operation of the various devices. Internal programming within the master controller establishes a repetitive time-sequence of windows for communications with the various device controllers for downloading control signals and parameters, and for uploading data indicative of system status and operation. The various device controllers include internal programming for operating the associated hydraulic devices as a function of control signals and parameters received from the master controller. Pseudo-devices are also connected to the bus for time-division multiplexed communication with the master controller and for performing overall system coordination and analysis.

Abstract: An electrohydraulic system includes a plurality of electrohydraulic devices individually controlled by microprocessor-based control electronics. The device controllers are connected in common by a bidirectional serial data bus to a master controller for coordinating operation of the various devices. Internal programming within the master controller establishes a repetitive time-sequence of windows for communications with the various device controllers for downloading control signals and parameters, and for uploading data indicative of system status and operation. The various device controllers include internal programming for operating the associated hydraulic devices as a function of control signals and parameters received from the master controller.

Abstract: A hydraulic system comprising a full flow supercharged variable displacement pump and a fixed displacement charge pump adapted to be driven by the same prime mover as the variable displacement pump for supplying fluid to the variable displacement pump. An orifice is provided in the supply line to the variable displacement pump, a circuit is provided from a point downstream of the orifice to tank pressure, and a feedback valve is provided in series with the circuit. The feedback valve comprises a pair of mutually and oppositely adjustable flow restrictions in series with said circuit. The restrictions are connected to the displacement varying means to vary them equally and oppositely in proportion to the movements of the displacement varying means.