1. Pneumatic valve positioner is mainly composed of I/P position conversion unit and intelligent valve control unit. The positioner and actuator form a feedback loop. The input device receives a 4-20mA current signal from the controller. The position feedback signal of the regulating valve is compared with the given signal value as the control variable in the microprocessor. Its deviation sends pulses of different lengths through the output port of the main control board to adjust the charging and exhausting speed and action, thereby controlling and driving the action of the regulating valve and determining the position.
2. Today, with the development of computer technology, electronic technology, communication technology and intelligent predictive diagnosis technology, the requirements for intelligent valve positioners are getting higher and higher. It is required that it must adapt to public lines for network communication and power supply, and its core pneumatic control components must achieve ultra-low energy consumption to ensure safe and reliable operation of the network bus control system.
3. The intelligent valve positioner has the characteristics of high reliability, high control precision, convenient function expansion and convenient communication. It fully meets the requirements of networked, integrated, and intelligent development of industrial control systems, and fundamentally overcomes the shortcomings of traditional mechanical valve positioners such as high power consumption, slow response speed, easy heating, mechanical wear, and electromagnetic interference. The intelligent valve positioner adopts pneumatic pilot technology to realize the internal air circuit control, that is, the small valve controls the flow of compressed air, and then the compressed air drives the large valve, so as to realize the flow control of the controlled medium. This idea of hierarchical control can be realized through the application of piezoelectric valves.
