384 Filling positon Stand by position Emptying position EPP4 Series Parker Hannifin Corporation Fluid Control Solutions Europe General Catalogue FCSE/0112/UK V2.2 07/2022 Description Operation The EPP4 Series is a family of electrically remotecontrolled pneumatic pressure regulators with closed loop integrated electronic control. It allows regulating the outlet pressure proportionally to an electrical control signal. The EPP4 regulator comprises a traditional servo-operated pneumatic pressure regulator, where the pilot chamber is fed y one or the other of two pulse width modulated 2-way solenoid valves. The pressure sensor measures the outlet pressure of the regulator and provides a feedback signal to the controller. Any difference between the control signal and the feedback signal is converted to a digital signal to energise the coil of one or the other 2-way valves to correct the position of the regulator. The control signal can be a voltage (0-10 V) or a current (4-20 mA). The inlet of the "Filling Valve" is connected directly to the main inlet P of the regulator; when energised this valve will fill the servo-chamber for increasing the pressure at the outlet A of the regulator. When the other "exhaust valve" is energised (reduction of pressure at the outlet A of the regulator), the pressure of the servo-chamber will be exhausted through a discharge orifice located between the cover and the body and directly fed to the atmosphere without silencer. The exhaust of the main regulated pressure will be made through the quick exhaust R. The use of a conventional silencer is recommended. Both solenoid valves assure the Filling or Emptying of the servo-chamber in order to increase or decrease the pressure at the outlet of the regulator. In rest position of the valves all ports are blocked. INTRODUCTION
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