The Multisensor Material Automatic Sorting System Design Based On PLC Control

Programmable logic controller(short as PLC), taking microprocessors as the core, combining with micro-computer, automation control and network communication technology, was designed for site control and widely applied for industry auto control devices and equipment. PLC has the advantages of high reliability, adaptability and expendability and so on. It could not only replace the traditional relay control system, but also be adopted for complex production process control and automation network. The research of this paper is based on the PLC multiple-sense for automatic sorting system trying to find a constructive method to upgrade existing similar systems.This research adopts Mitsubishi FX-2N Series PLC to undertake major program control tasks. At the same time, sensor technology(including inductance and capacitance and photoelectric sensor), frequency convertor technology, electromagnetic technique, pneumatics technique and touch screen technology are systematically integrated, with an aim to demonstrate PLC’s performance in process control system and set a good example of enterprise automation.The design of this system is based on such an idea that the PLC-controlled multi-sensor material sorting system employs modular design and each working unit can make design independently and achieve different functions. The system consists of feeding, inspection, recycling, conveying and sorting stations. The program was mainly controlled by PLC, the convey band was controlled by frequency convertor while different sensors could inspect the materials and their colors as well as the differentiation of item positions. In the end materials would be transferred to specific locations through mechanical hands. Any oppositely-placed materials detected would be conveyed to recycle station as unqualified items.On the basis of the needs of auto sorting, this paper posed a scheme of electrical control based on PLC, with an aim to realize reasonable connection between systematic control and mechanical action. Reasonable connection and matching between controlling and mechanical action was achieved in this paper based on the auto sorting function requirement and the electrical control system design of PLC. How to debug the system on line, test the reliability of system operation and the accuracy of sorting are also discussed in this paper. The test outcome has shown this system design has characters such as high precision on control, easy and simple operation and good reliability and that all performance indexes have achieved the design requirements. It is hoped that the outcome of this paper can contribute to the development of similar systems.