Control system

A system for remote proportional positioning of a plurality of hydraulic directional control valves, comprising

• a. a signal transmitter having a plurality of manual operating members, a pulse generator for repetitively producing a pulse group comprising an initial pulse and a plurality of control pulses, one for each operating member, following in time-spaced succession after the initial pulse, and means for changing the time spacing of each control pulse from the next preceding one of the pulses of the pulse group in accordance with the position of the associated operating member,
• b. a plurality of electrohydraulic converters associated with respective ones of the operating members and adapted to be connected to an associated one of the control valves to be positioned, each such converter including means for producing a hydraulic positioning signal proportional to an electric input signal, and
• c. a transmission unit for the transmission of the pulse groups from the signal transmitter and for deriving from the pulse group an electric input signal for each converter, including a decoder having an input for the pulse groups from the signal transmitter, means for deriving from each control pulse of a received pulse group an electric signal of a predetermined magnitude and of a duration proportional to the time spacing of that control pulse from the next preceding one of the pulses of the pulse group and shorter than the time spacing of two successive pulse groups, and means for feeding this signal as an input signal to the associated converter.