Sunday, August 15, 2010

Smart gate valve actuator system hardware component


Intelligent controller based intelligent, high reliability, strong anti-interference ability, low costs, in principle, control, 8-bit microprocessor core MC68HC908SR12 (SR12), the main motor control circuit using power electronics technology.







SR12 has the speed, functionality and price, strong and low. Its maximum operating frequency of up to 8MHz, 512 bytes of on-chip RAM, 12K bytes of on-chip FLASH memory, 14-channel 10-bit A / D, and SCI, I2C, SPI and other communication interface [1,4].







System Application SR12 within the A / D input signal and valve position to control signal acquisition, the use of PWM output through the filtered position signal, using I2C bus to communicate with external memory AT24C08 memory settings, using SCI interface through the MAX485 and the Upper machine data exchange, made full use of the chip's internal resources and save costs.







2.1 The signal input part of the







The use of SR12 internal A / D conversion, the analog input signal and valve position feedback of the analog signal to quantify. With REF02 as A / D reference voltage, the temperature drift coefficient of 3PPM / ℃.







2.2 The signal output section







SR12 has 3-channel 8-bit high speed PWM, each channel has a separate counter, selectable PWM input clock to generate a variety of PWM frequency, and automatic phase control. To use one all the way as the analog output PWM signal, the other two-way as motor control signals. Choose the same time, I / O port PTB6 as a relay switch output of the control signal.







2.3 Input-output isolation







System when used in the industrial scene, involving a variety of instruments, sensors and implementing agencies, for various reasons due to the introduction of signal interference, as well as the dangers of strong voltage signal. To ensure the security of the system to ensure testing accuracy and reliability of operation, using optocoupler LOC210 isolation of input and output signals.







2.4 Communication part of the







In order to complete the industrial field remote control and networking needs, the system supports RS485 communication. Level conversion chip MAX485. Practical work, they can carry out long-distance communication with the host computer to carry out operation mode to set and monitor operation status.







2.5 motor drive part of the







The use of electric motor-driven electronic switch TRIAC BTA16. Bidirectional thyristor with switching speed, long life, no spark and pull characteristics of arc phenomena [2], to ensure the implementing agencies under the conditions at high temperature long-term reliable operation, while helping the motor protection. Between the main circuit and the CPU use of opto MOC302X drive, as shown in Figure 3, the figure for the electrical load ZL.







In the design, MOC3020 diode forward current of 15mA, MOC3021, and MOC3023, respectively 8mA and 3mA, it can be MC68HC908SR12 the I / O port with sink directly drive. RC absorbed in practical work, the actual parameters need to loop motor parameters (ZL) to determine the difference.







Note that, MOC302X the voltage is 400V, if the motor need to work at 380V or under the motor back EMF relatively large, we should use MOC308X series.







3 Software Design







Controller's software mainly by the main program, man-machine interface, procedures and automated debugging, fault handling, A / D conversion and data processing, manual operation composed of fault handling routines. The main program flow shown in Figure 4.







In the implementation process, to judge the fault condition and found that failure, the immediate alarm display, while the output volume of a group of relay switch signal to the user, and cut off electrical power supply.







System uses four key methods used to realize the complex system of control and parameter settings. Four keys defined, respectively F (Function), U (Up), D (Dowm), S (Shift). F for the function keys, click here to enter setting menu, repeatedly press F key to exit the menu after. U, D keys to increase and decrease respectively represent the current values or preferences, in the manual operation on behalf of up or down commands. S as a toggle key, you can change the current input focus, with the U, D keys, can easily achieve any number of input.







In the motor control algorithms using PID regulation, to avoid overshoot, oscillation occurs, while an optional direct proportional control and proportional control mode + stepper control, so that the system can be applied in different types of motors.







System software design allows the valve can be adjusted at both ends of position, as long as the adjustments made after a good limit switch auto-tuning (F, S key while pressing the 10s) can greatly facilitate the users. System also provides RS485 communication protocol, the user can programmatically control valve through the host computer so that networked communications and computer-controlled valve more convenient.







4 Conclusion







Of the system all the major functional blocks concentrated in the single-chip microprocessor, reducing the system cost, improved reliability, reduced size, can be directly installed in the actuator without the need for change within the body of the original machinery, which not only facilitates the the existing implementing agencies of production, but also conducive to the transformation of the existing old equipment. At the same time, the system's hardware design fully into account the industrial surroundings of the scene and adopt a comprehensive anti-jamming measures and fault protection measures so that the system can be applied in industrial surroundings of the scene.







The system has been actually put into production, at present in a variety of industrial environments work well.



gate valve manufacturer Cast Steel Gate Valve Stainless steel gate valve  Jacket gate valve  Forged Steel Gate valve  Knife Gate Valve  Cryogenic Gate Valve  Plate Gate Valve  



We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com

No comments:

Post a Comment