Abstract
This article places the PLC various hardware part with emphasis the design and the introduction, in the PLC trapezoidal chart compilation, has made the careful analysis to overall system's project work. in the design take vending machine's basic principle as well as the work flow, then by a transaction process as an example, divides into several blocks the transaction process, then carries on the programming separately to the block. Explained specifically the programmable controller's in vending machine function, the procedure involved the vending machine work major part process. Enhanced system's stability using the PLC control's vending machine, the guarantee vending machine has been able the long-term stability movement. Defers to the overall design process “asks the question, the analysis question, solves the problem” the guiding ideology, has made the careful elaboration to overall system's project work.
key word: Programmable controller vending machine trapezoidal chart
