An Analysis System Of CO₂ Arc Welding Based On C8051F320

This paper has developed an analysis system based on MCU-C8051F320,by using CO₂ arc welding short circuit transfer process as a studied object.And introduced an analysis model which was set up according to characteristic parameters of arc voltage and welding current. Based on this analysis model, the system can calculate spatter ratio, evaluate welding process stability quantitatively.Hardware circuit consist of Hall sensors,USB type MCU-C8051F320 and PC. Arc voltage and welding current are signal source. Because of C8051F320 which integrates USB controller and A/D unit, this hardware design is more convenient and the system has higher transmission speed. Compared with general data acquisition card, it is much cheaper, more flexible .And it also has the characteristic of plug&play.Software system are composed of firmware, USB driver and application program. The firmware was developed by C51 language. The USB driver was created by VISA3.2 which is a high-level application programming interface developed by American National Instrument Corporation. Application program was developed by LabVIEW,a virtual instrument programming software, and MATLAB, a Math software. In combination with MATLAB's powerful data handling function, performance of the analysis system has been improved greatly.With this system, we can implement signal real time acquisition, dynamically display and data save; wavelet soft-threshold de-noise; extract the characteristic parmeters of arc voltage and welding current(including arc time, short-circuit time, short-circuit peak current, short-circuit current growth rate, arc power,short-circuit power, normal short-circuit transfer frequency, etc); draw instantaneous U-I curve, get probability density distribution about arc voltage and welding current, frequence distribution curve about arc cycle and short-circuit cycle; analysis spatter ratio of short circuit trandsfer quantitatively, and so on. It has been proved that the spatter ratio got from the analysis system is in accordance with the practical spatter ratio. Therefore, this system provides a easy way to evaluate the welding process stability directly and precisely.