Development Of The Control System For Micro Inductor Automatic Production Equipment And The High Precision Resistance Spot Welding Inverter

The great needs of communication devices, IT products and consumption digital products dramatically promote the growth of chip inductor industries, and the quantity of demand for chip inductors reaches tens of billions. However, the characteristic of shape irregularity and type variety makes it not an easy thing to organize massive production like other chip components. Traditional productive enterprises in Japan or US either focus on the research of materials used in multilayer chip inductors, either on the development of fine spot welder. They are not free to involve in the invention of automatic machine for wire wound chip inductors. Up to the present wound chip inductors are still mainly produced by hand through recuiting large numbers of young workwomen, which is low efficiency and lack of quality guarantee. ThereforeIn this paper, two subsystems, control circuit based on DSP for high precision soft-switching resistance spot welding(RSW) inverter and Control System based on PLC for the equipment, are discuss.Aiming to gather the welding parameters of RSW accurately and real-timely, the topological structure and operating principle of the main circuit of the soft-switching RSW inverter power are studied, and the hardware circuit with TMS320LF2407A digital signal processor is designed, and collect the parameters of welding current ,welding voltage and so on through True-RMS transform circuit in this paper; in order to implement the communications between PLC and DSP, simple but effective RS-485 communicate hardware circuit is designed. Based on the hardware circuit above, embedded real-time operation systemμC/OS-Ⅱis applied in DSP. ApplyμC/OS-Ⅱas software develop platform, the application program of phase-shifting PWM control and serial communication are developed in this paper. It advances the reliability, stability and intelligence for the DSP system.Finally, the control system adopt Programmable Logic Controller (PLC) to be the main CPU, two motion control module, FX2N-20GM, are utilized as auxiliary units for PLC, realizing the motion control of the whole machine; and the PLC to be the main master station, through RS-485 bus to communicate the control system of RSW inverter and the solder joint quality inspective system. The rules of modeling for PLC control system is presented based on Petri nets .By use of Petri nets, we can model the PLC control system and analyze the performance, and transform the model into PLC program.The high precision soft-switching RSW inverter and Control System based on PLC are already debugged in the paper. The debug results indicate that this micro inductor automatic production equipment can produce the chip inductor effectively and intelligently.