The Variable Polarity Tig Welding Control System Based On AT89S52

Variable polarity argon tungsten-arc welding is a perfect arc welding method of welding aluminum and its alloys. The current is variable polarity current, The zero pass speed is rapid and it is propitious to arc stiffness; The amplitude and time of plus-minus semi-vave can be accommodated independently. Under the condition of forming well catelectrode atomizationt, Tungsten electrode burning loss can be reduced in high limit,foming perfect welding process. The welding source adopt the inversion control technique, the control system certens on computer control system, the characteristic of control arc welding electrical source is high degree of accuracy and multifunction. At present inversion arc welding source controlled by computer control system is the development direction of welding source.The inversion main circuit, basic control circuit, drive, protective circuit and computer control system control system of vriable polarity TIG welder control system are designed in this task. The first inversion circuit adopts the whole-bridge structure and PWM control technique, carring out by integration control CMOS chip; the second inversion main circuit adopts the push-pull mode structure, the second inversion process is controlled by the adjustable impulse generated by the timer of computer control system. The drive is designed by extending discrete component centering on thick film integrated circuit EXB841 and M57962. Protective circuit designs overflowing overheat overpressure and low-voltage protection.The A/D and D/A interface circuit and display interface circuit are designed centering on AT89S52 depended on single chip computer control system. The C language and assembly language are used to design related software. By using such way, the plus-minus half wave time and current amplitude can be adjusted according to different requirement. The output parameters of welding machine can be controlled. On the other hand, the SCM control system carrys out the control of the work time sequence according to the the require of welding procedure, friendly human-computer interaction terrace is supplied by LCD and opto-electrical knob, which makes the welding parameters can be set and accommodated expediently by operators.Software is designed through the modularization design method. The software design and the debugging of every function module are accomplished in Keil environment. After each debugging, delete special program segments that wrote for debugging, Join every function module and debug the program. The experimental result indicates that the hardware is designed in reason, the software extend theanticipative control impact.