《Proportional and Servo Valve Technology》.pdf

The ability to achieve automated stepless control of digital, or on-off, devices. The introduction of the pressure and flow rate in fluid power systems has microprocessor, and hence, the PLC (programmable logic undergone major development in the past twenty-five controller) opened the door to a great amount of control years. Electrohydraulic servo valves were invented in the late options to machine designers. The operation sequence of a 1930s as a high tech, though high cost, solution to motion machine was no longer hardwired in relay logic. While control needs. The mid-1980s saw the practical introduction Boolean operations were possible in relay logic, it was of proportional valves as a viable and reasonably priced inconvenient to do so, as well as difficult, expensive, and alternative to servo valves. This article will explore the time consuming to accomplish. The common introduction technology used in these proportional and servo valves as of PLCs and proportional valves greatly expanded the well as attempting to shed some light as to what type of control options available to machine designers. valve may be most appropriate for a given application. The initial proportional valves that appeared on the If true, stepless control of pressure or flow wasn’t that market are what are now commonly termed “open-loop” critical to the operation of a machine, preset pressure or valves. In contrast to mechanical feedback (MFB) servo flow control valves could be achieved by having a bank of