A periphery is needed to supply and control the servo-cylinders.
This periphery is limited to the valve level and is comprised of
connection and servo-valves.
Connection valves supply a hydraulic oil consumer (servo-cylinder,
etc.) with hydraulic oil.They are located as close as possible to
the consumer and work according to the quiescent current principle
(no current = closed).
Servo-valves are electrohydraulic control valves for controlling
a source of hydraulic energy (pressure, flow). In conjunction with
electrical control circuits and hydraulic cylinders in the servo-cylinder
system they serve to convert hydraulic energy to controlled load