SAE ARP490A

The recommendations contained in this recommended practice are confined to the input and output characteristics of electrohydraulic flow-control servovalves. The information presented should be useful in standardizing the terminology, the specification of physical and performance parameters, and the test procedures used in conjunction with these components.The recommendations do not restrict nor attempt to define the internal design characteristics of servovalves. As such, the material is equally applicable to servovalves having different internal functioning, different ratings, different physical size, etc. In certain instances, standards for valve design are recommended to increase component interchangeability, as, for example, pigtail color-coding, valve polarity, mounting bolt and fluid port locations.The specifications contained herein should be adequate to describe electrohydraulic flow-control servovalves. Additional specifications may be necessary to define special requirements for specific control systems. Also, specialized test procedures may be necessary to measure servovalve performance in these unusual specification areas. These considerations are beyond the scope of this recommended practice.