FBM230 FOXBORO
development of data communication technology,users have strong requirements for openness,and the synchronous development of fieldbus technology and Ethernet technology,the PCS system composed of PLC is slightly better than the current situation of DCS’s openness.Rockwell AB has formed a multi-layer structure system,including Ethernet Net,Control Net,Device Net,and ASI fieldbuses(which are also compatible with the original DH+network).Siemens has proposed the S7 Routing network,which consists of two layers:Profibus-DP and Industrial Enternet,in addition to the Profibus-DP communication network and Profibus-FMS network.The internet is still developing,and China should actively invest in it.
In 2001,China’s mechanical industry became a new highlight of industrial development,with a total output value increasing by 17.15%compared to the previous year.The production of automobiles ranked among the top 10 in the world,and the production of machine tools ranked fifth in the world.The profit of the mechanical industry increased by 33.35%,accounting for over 60%of the newly added profit of the entire industry.Exports have also shown promising growth.The machinery industry proposes to implement networking.PLC practitioners should have a clear understanding of this,and pay special attention to the openness of networking,the performance/price ratio of network
composition,and the reliability,security,and progressiveness of the network.
The upward connection of the network is an internet problem,and the downward connection is a fieldbus problem.In addition,the existing network can use Ethernet”e network to the bottom”mode,the network can use client/server mode,browser/server mode,producer/consumer mode,and the interface software can use OPC mode,all of which need to be further implemented.PLC and intelligent MCC motor control center,NC/CNC numerical control equipment matched with CNC machine tools,as well as systems connected with other operation control systems,electronic control equipment,frequency converters,and soft starters;PLC should cooperate with DCS and act as a remote I/O station for DCS
needs to cooperate with IPC for division of labor.In addition to using IPC as the human-machine interface,it is also feasible to use IPC as the I/O component of software PLC;In addition,the relationship between PLC and emergency shutdown safety systems(ESD),as well as the relationship with three-dimensional warehouses,robots,CAD/CAM,and so on,must be well handled.In short,PLC should be compatible with various new technologies,making it a true”computer
The application field of PLC is broad,and there are many areas that urgently need to be explored,such as for customs transit vehicle certification(Shenzhen Yantian)and automatic drug sales(several traditional Chinese medicine stores),which have already been examples in China.In addition,in discrete event systems,such as highway network traffic flow(vehicle counting,passenger counting,and residence time measurement),logistics systems,flexible manufacturing systems(agile manufacturing systems),and all non-standard on-demand service systems,PLC can be used to model,take countermeasures,and optimize.The future of PLC is promising,and all pessimistic arguments are untenable.As for technological progress,it will take some time for PLC to integrate with other technologies and even disappear!
