Application Of Embedded Technology And CAN Bus In Vending Machine Network

The vending machine which has been widespread use of has made it so easy to go shopping for people and has created many business opportunities.But vending machine which is very scattered is prone to failure and out of stock easy.So it is difficult to manage all the vending machines for operators.To solve this problem,this paper puts forward the design of vending machine monitoring system based on the CAN bus.The system that manages vending machines in the network with PC as monitoring center is a distributed control system.First of all,this paper compares several influential field bus,and eventually selects CAN bus as the system communications network,building a network structure of the system.And by analyzing the system requirements the paper determines the system's hardware and software design.Secondly,this paper details the hardware and software of the systems.Hardware design of vending machine controller is the main task of system hardware design.In order to ensure system reliability,the controller is divided into two boards in the structure of hardware.One is main board,the other is control board.The main board is responsible for management and payment,and the control board is responsible for the mechanical and electrical drive components,to achieve effective control of the executive body.The two communicate through the CAN bus.What is more,some control boards can share the same main board to save costs.System software is composed of the software of vending machine controller and the software of monitoring center.The distribution and scheduling for tasks is the main task in the design of software of vending machine controller based on real time operating systemμC/OS-Ⅱ.The main role of the software of monitoring center developed by VB and the database management system MS SQL Server 2000 is to monitor the vending machines in the network.In addition,the paper works out the CAN network application layer protocol by analysising CAN bus communication.Lastly,part of the system function has been tested in laboratory.The expecting results for the design of vending machine monitoring system based on can bus and embedded technology have been achieved.