Digital Control System of Gas Pressure Regulator

Many technological processes require a smooth change in the parameters of compressed air, which is provided by the use of control valves with an electropneumatic actuator. Regulator with electropneumatic actuatorss are becoming more popular than mechanical actuator devices due to their high degree of automation, easy setup, self-diagnostics, and the ability to transmit data to the upper automatic control system. One of the main problems in creating this type of regulator is to ensure the quality of the control system and the reliability of the diaphragm actuator control valves, which are prone to clogging and jamming in low-purity environments. This work is devoted to the study of gas pressure regulator with a pneumatic diaphragm actuator and a digital positioner based on a block of on/off solenoid valves operating in pulse-width modulation mode. Due to the use of on/off solenoid valves, instead of proportional valves, the cost of the regulator is reduced and low sensitivity to contamination is provided, because on/off solenoid valves have a relatively large flow area compared to proportional valves. The paper describes the mathematical model of the regulator developed in Simcenter Amesim software package. The influence of the pulse width modulation carrier frequency on the on/off valve control characteristic is shown. The transient characteristics of the regulator are obtained with a step change in the set pressure and the value of the consumer load. The results presented in the article may be interest to designers of control valves with pneumatic diaphragm actuators controlled by programmable logic controllers.