as modern enterprises expand production scale, business-to-production process reliability and production efficiency have made new demands, in this case the implementation of automatic control of production to become an inevitable choice for enterprises. Programmable Logic Controller (PLC) is a new universal control device. He will computer technology, automatic control technology and communication technology integration, to become one of the pillars of modern industrial automation, is the realization of FA (Factory Automation) and core equipment. U.S. Allen-Bradley (Allen - Bradley, referred to as AB) produced a large number of programmable controllers used in automation. According to statistics, he was in the North American market share above 67% [1]. AB programmable controller products, the main PLC-5, SLC500 and MicroLogix1000 series controllers, recently launched a more powerful ControlLogix System , as A-B, the next generation of control system products ControlLogix family PLC control system with its advanced technology, simple structure, high reliability and strong floating point capabilities, widely used in many domestic metallurgical, chemical industry automation control systems in.
1 ControlLogix control system characteristics
ControlLogix control system looks like a programmable logic controller, but he did not stop there. ControlLogix structural system is a technologically advanced control platform, he integrates multiple control functions: sequential control, motion control, drive and process control. Traditional programmable logic controller is different, ControlLogix system in any size are modular. According to the specific application to select the appropriate amount of memory, the controller number and type of network, this flexible structure allows multiple controllers use the same rack, network and I / O modules. At the same time, ControlLogix system has excellent performance quality, the main features are as follows [2]:
(1) easy and seamless process on other network controller transparently send and receive information, good compatibility.
(2) Fast ControlLogix backplane to provide structure in the high-speed data transfer bus, Logix5550 controller provides high-speed transmission control platform.
(3) can be configured according to the needs of industrial production increase or decrease in the number of controllers and communication templates can be used in multiple controllers within a rack.
(4) provides a high strength industrial ControlLogix platform and can withstand vibration, high temperature and a variety of industrial environments, electrical interference.
In addition, its compact structure, can effectively reduce the distribution disk space; may need to achieve between the controller and the network bridge; multiple controllers, I / O and communication module pull template can be any combination. In addition, the plug can be charged without having to disconnect the system from a module to other modules, and provides removable terminal blocks, easy to use, easy to maintain. ControlLogix system uses RSLogix5000 programming software, he can run on Windows NT32 b of the operating system, its superior performance, and provides reliable communication and diagnostic features, with a common user interface and feature set, with a flexible, easy to operate editor, click on the conduct I / O configuration. The system monitoring software RSView32 Chinese, Chinese display, modify, convenient, easy to operate.
2 ControlLogix system components
ControlLogix control system microprocessor core, the advanced control technology, communications technology, computer technology, CRT technology and live instrumentation combined organically to achieve centralized monitoring of the production process, focusing operation and decentralized control, provided for the production of a strong guarantee. As the amount of memory the system, controller number and type of network can be selected according to the specific application, so compared to other programmable control system, its structure more flexible and more convenient to use.
Logix5550 (controller) ControlLogix system is the Logix5550 controller, the processing speed of 0.08 ms / K command, the standard memory configuration is 160 kB, expandable to 2 MB, a Logix5550 controller supports 12 800 or discrete 4 000 analog I / O points, consistent with IEC1131-1 to provide multi-tasking operating system environment can support up to 32 missions, 31 of which time slots set by the user, to support long file, the variable name [1]. Logix5550 microprocessor core, using advanced process control technology, communication technology, computer technology, responsible for detection and control of the production process is the data acquisition, process control section. Through the configuration and programming, feature rich motion control, sequence control, drive and process control, computing capabilities, can be directly collected from the scene of various types of process data, after processing, computing, it will detect the signal sent to the operating station to monitor, control signals will be sent to the scene. High reliability, high speed scanning handling characteristics, and self-diagnostic function.
RSView32 is the operator and the ControlLogix system of man-machine interface that can process large Fan Wei s Shengchan surveillance and operation are, also can process the information collected Chu Li and Bao Cun, the technical parameters were Shishixianshi and alarm, to achieve on the manufacturing centralized monitoring, centralized operations, centralized display, focus, with data processing, preservation of historical data, alarm display and printing, report generation, multi-display and the implementation of the control loop operation and other functions, to facilitate the production control and management. <BR>
Main frame is the core part of the controller, mainly by the controller (Logix5550), power modules, communication modules (CNBR), input / output modules and other components.
Expansion rack by the variety of signal input / output module composed of these modules include: Analog (4 ~ 20 mA) input / output module, PT100 RTD temperature input module, 220 VAC digital input / output modules and Communication Module (CNBR).
Ethernet (Ethernet) the Ethernet using the standard "Simple Network Management Protocol (SNMP)", using the Ethernet processor, built-in communications capabilities, using standard commands available Ethernet and high-performance peer communication . Windows 95/NT operating system on the host computer, through RSlinx software, their applications directly to the Ethernet communication between the processor; use RSLogix5000 programming software on the processor control program for remote programming, debugging; with RSView32 human-machine interface software for comprehensive data collection and information management [1].
Control Network (Controlnet) mainly to achieve the controller, input / output modules and RSView32 (PC) communication between the linked host computer and slave bridge. ControlNet networking technology built on open innovation program of Producer / Consumer way, the way the Internet allows all nodes in the same time a data source to read the same data, so they have a higher throughput, and multicast communications capabilities to many controllers can share data entry and interlock on the transfer of data to achieve better performance and reduce the demand for programming [3].
With A, B two communication lines for the system provides redundancy to improve system reliability, communications line failure in a case can be automatically switched to another root, under normal circumstances, is always only one in working condition.
CNBR (Communications Module) is a link rack with the system link. Digital systems can be used to simulate the volume of data transfer and exchange. Communication module to support open network, such as Etherner, ControlNet, and DeviceNet, also supports A-B s DH + network and the RIO network. Gateway products are all the communication module, without processor programming. Programming software migration tools can also PLC-5 and SLC500 the program moved to the ControlLogix processor.
3 Conclusion
The reformed system work in the use of high reliability, support for online parameter changes and configuration, to production has brought great convenience. The system also has a low price, high integration, compatibility, openness and good features, while ensuring high reliability based on a thorough solution to the original control system plagued tube digestion problems.