Research On The Real-time Performance Of Cigarette Making Machine Control System Based On Hybrid Fieldbus

With the continuous development and extensive application of fieldbus technology,it has been a common way of networking in industrial control system that different fieldbuses with their own advantages are integrated in one network control system to form a Hybrid Fieldbus Control System.In industrial applications,real-time performance is a key technical indicator that reflects the performance of the control system.At present,there are many studies on the real-time performance of Single Fieldbus Control System,but few on the real-time performance of Hybrid Fieldbus Control System.Therefore,it's of great significance to do some research on the real-time performance of Hybrid Fieldbus Control System.Cigarette Making Machine Control System is a complex industrial control system which combines fieldbus technology,computer control technology and network technology together.In this paper,I choose to build a Cigarette Making Machine Control System based on hybrid fieldbus and do some research on its real-time performance.Firstly,the paper introduces the research status and development trend of Cigarette Making Machine Control System and analyzes its control function requirements.Considering the compatibility with current Cigarette Making Machine Control System and that Tobacco Technology Center proposes to build a Cigarette Making Machine Control System based on IPC and EtherCAT,the hybrid fieldbus Cigarette Making Machine Control System based on EtherCAT and PROFIBUS is built.Secondly,the communication process and communication delay of the hybrid fieldbus Cigarette Making Machine Control System are analyzed.And the calculation methods of the communication cycles of EtherCAT,PROFIBUS and K-Bus are given.Specially,this paper proposes a method of calculating the delay of different types of EtherCAT slaves,through which EtherCAT network delay of various topologies can be calculated.Thirdly,the paper analyzes the real-time requirements of Cigarette Making Machine;and the requirements of the I/O response time and the minimum sampling period of the control system are obtained.After that,the I/O response time and the minimum sampling period of the hybrid fieldbus control system are estimated,and the feasibility of the constructed hybrid fieldbus control system applying to the control of Cigarette Making Machine is analyzed from the perspective of real-time performance.Finally,the experimental platform of hybrid fieldbus control system which has similar structure to the constructed hybrid fieldbus Cigarette Making Machine Control System is constructed.On the experimental platform,experiments of the EtherCAT slave delay and I/O response time of the control system are carried out.The experimental results show that the proposed calculation method of EtherCAT slave delay is correct and the estimation method of I/O response time of the hybrid fieldbus control system is reliable.By analyzing the experimental results of EtherCAT I/O response time and EtherCAT.PROFIBUS I/O response time,it can be concluded that the average response time of EtherCAT I/O is about 1.5 to 2 times the PLC cycle time and that of EtherCAT and PROFIBUS I/O is about 2.5 to 3 times the PLC cycle time.