The present paper design was by the microcomputer - PLC constitution automat supervisory system, this article elaborated automat and the development, as well as it in the domestic and foreign development present situation, has carried on the proof to automat plan, introduced PLC composed, the characteristic as well as the principle of work basically, to carried on a more careful elaboration by the microcomputer - PLC constitution vending machine system overall design process.
Chooses PC machine in the design to take the host workstation on position machine, the lower position machine uses PLC to make the controller, each PLC controller controls a automat subsystem, three PLC controllers respectively be from the workstation 1, from the workstation 2, from the workstation 3, in the article exhaustively introduced the automat various hardware composition, and has completed the PLC exterior wiring diagram. In the article has manufactured on the position machine user management contact surface, applies the VB6.0 software carries on to on position machine user management contact surface procedure as well as the host workstation signal procedure compiles and debugs; When PLC trapezoidal chart compilation, in the article uses is Siemens PLC trapezoidal chart special-purpose translation software STEP7 carries on the compilation.
The present paper key point places the PLC various hardware part the design and the introduction, the PLC trapezoidal chart compilation and in the various workstation procedure compilation. Defers to in the overall design process “asks the question, the analysis question, solves the problem” the guiding ideology, has made the careful elaboration to the overall system design work.
Key words：PLC; Automat; Ladder logic diagram; VB