Do you know the control method and principle of pneumatic valve actuator?

X5045 pin arrangement, SO serial data output terminal; <SI serial data input terminal; <SCK serial clock output terminal; <WP write maintenance input terminal. There are 8 pins in total, and the functions of each pin are as follows:

CS circuit selection terminal, active low;

SO serial data output;

SI serial data input terminal;

SCK serial clock output;

WP write maintenance input, active low;

RESET reset output;

Vcc power terminal;

Vss ground terminal.

Due to the increasing number of control methods and means, the digital circuit part mainly includes: single-chip microcomputer, power-down protection, two-way monitoring pulse input signal, and two-way normally open and normally closed conversion contact output. <The commonly used 51 series microcontroller AT89C4051AT89C4051 is a low-voltage, high-performance CMOS8-bit microcontroller in the design scheme. In actual industrial life and industrial control, there are many methods used to control pneumatic actuators, and the following are commonly used.

Development of Intelligent Display Instrument Control Based on Single Chip Microcomputer

The intelligent display instrument is an instrument used to monitor the working status of the valve and control the working of the valve during the execution period. It monitors the working status of the valve through two-way position sensors, determines whether the valve is in the open or closed state, and records the number of the valve switch through programming. And there are two 420mA outputs corresponding to the valve opening and two-leg normally open and normally closed output contacts. Through these output signals, the switching action of the valve is controlled. According to the requirements of the system, the intelligent valve display instrument can be divided into three parts to design from the hardware: analog part, digital part, key/display part.

1. The part of the analog circuit mainly includes three parts: power supply, analog input circuit and analog output circuit.

The power supply locally supplies the entire circuit energy, including the analog circuit, the digital circuit and the display energy supply. In order to realize the remote control of valve opening and reading, it is necessary to transmit the valve opening information to other control instruments, and the control instrument can set the valve to a certain opening from a distance. The system needs 1 channel of 420mA analog input signal and 12 channels of 420mA analog input signal. output signal. The analog input signal is converted into a digital signal corresponding to the valve opening through A/D conversion, and then sent to the digital local microcontroller. After filtering it in the microcontroller, the valve opening information can be output through D/A conversion. It becomes an analog signal output, which is used to connect the display instrument to display the valve opening or connect to other control equipment. In this design system, all digital data adopts serial input and output mode. In order to save chip resources and space, when the input 420mA analog quantity is converted into digital quantity, the existing system of 4-channel DA chip and single-chip microcomputer is used. Resources are combined for use with 8-bit AD.

2. The part of the digital circuit mainly includes: single-chip microcomputer, power failure protection, two-way monitoring pulse input signal, and two-way normally open and normally closed switching contact output.

In the design scheme, the commonly used 51 series microcontroller AT89C4051AT89C4051 is a low-voltage, high-performance CMOS 8-bit microcontroller with 4K bytes of erasable and reprogrammable read-only flash memory. By combining a multi-function 8-bit CPU flash memory in a single chip, it is fully compatible with 80C51 and 80C52 in performance, instruction setting and pins.

Some valve parameters previously set in the meter need to be adhered to, taking into account when the system is powered down or restarted. The data memory in the single-chip microcomputer does not have the function of power-down storage, so a chip with power-down storage function X5045X5045, a programmable circuit that integrates three functions of watchdog, power monitoring and serial EEPROM, is expanded off-chip. This combination design can reduce the circuit's demand for circuit board space. The watchdog in X5045 provides protection for the system. When the system sends a fault and exceeds the set time, the watchdog in the circuit will respond to the CPU through the RESET signal. X5045 provides three time values for users to choose and use. The included voltage monitoring function also protects the system from low voltage, when the supply voltage falls below the allowable range, the system will reset until the supply voltage returns to a stable value. X5045 memory and CPU can be interfaced by serial communication. There are 4069 bits in total, and data can be placed in 5128 bytes.