Design Of Distributed Measure And Control System Based On EtherCAt Fieldbus

Measurement and control are two important parts in modern industrial production.With the development of science and technology,the field bus control system has replaced the traditional centralized control system and distributed control system,which has become the mainstream of the measurement and control system.Field bus technology is the foundation of modern measurement and control system,but the traditional field bus technology has the shortcomings of the standard is not uniform,which restricts the development of fieldbus technology.Compared with the traditional field bus,industrial Ethernet has the advantages of uniform standard,flexible topology,fast transmission speed,and gradually become a new direction of field bus technology development.Ether CAT bus is the fastest industrial Ethernet,so in this paper,the research of distributed measurement and control system based on Ether CAT bus is of great significance.Firstly,this paper introduces the principle and operating mechanism of the Ether CAT bus,and designs the overall structure of the distributed measurement and control system based on Ether CAT bus.The system contains a single master and multi-slavers,the master is the control center of the measurement and control system,manages the Ether CAT bus communication function between the master and slavers and realizes the human-machine interface;while the slaver receives and processes the Ether CAT data frame transmitted by the master station and implements the specific measurement and control task according to the content of the data frame.Secondly,the design of the hardware structure of the measurement and control system is completed.The master is a PC with NIC network card,the hardware of slavers includes communication board and control board,which were designed independently.In terms of communication board design,chose ET1100 as the slave controller,and designed the Ethernet interface circuit,PDI interface circuit and ET1100 peripheral circuit;In terms of control board design,chose the STM32F407 as the slave microprocessor to design the switch quantity,the pulse quantity and the analog quantity input measurement and the output control circuit.On this basis,draw PCB diagram and make the circuit board.Then,the function of the software of the control system is designed.In terms of master's software design,using software controller Twin CAT as the master controller,the design of the PLC control program and man-machine interface to achieve the master control function;Design device description file,so that the master can get the configuration and status information of slavers;The slaver software design includes the communication software design and control software design,communication function software is composed of three parts,the driver layer,the Ether CAT protocol stack and the Co E protocol,and measurement and control function software can realize the input and output control function of the switch quantity,the pulse quantity and the analog quantity.At last,experimenting on the measurement and control system and testing the operation condition of the system.The experiment platform is set up by using the hydraulic four ball machine,and test the actual performance of measurement and control system through the capture test,real-time synchronization test and measurement test three test.Experimental results show that the system is stable and reliable,and achieves the expected goal.