1 PLC, IPC, PC-Based PLC
The rapid development of PC technology to IPC (industrial computer), and IPC-based application technology to the rapid development also. At the same time, Internet technology and all production process and control information process of information integration and development, and can Internet / Intranet browsing information flow in the manufacturing production process, operation and monitoring field intelligent devices, IPC bear more and more SCADA machine interactive control tasks and coordination at lower levels of small controller or intelligent field device control task. Overall, IPC s most suitable for automation and control platform. But as the traditional mainstream ???ì??????§ PLC, it has good stability, high reliability and ability to control the logical order of advantages, such as automation and control has an irreplaceable advantage. But one big regret: their closed architecture, a closed system (R & D must have his or OEMCPU, chipset, BIOS, operating system, ladder programming software), will inevitably result in less open barriers to its application, has also increased User maintenance difficulty and integration costs. It was asserted that in the near future, the controller will gradually replace the PC-based PLC control equipment has become mainstream. Improve the situation, the traditional PLC manufacturers are gradually PC-based PLC functions (such as SiemensWinAC), while the IPC IPC manufacturers have gradually PLC logic control functions, thus enabling PLC and IPC functions and specifications are closer, thus the emergence of technology based on the middle of the controller PLC, IPC: PC-Based PLC.
PC-Based PLC, also known as embedded controllers, it is no longer the IPC board as to increase as the main chassis structure, with the combination such as A / D, D / A, DI / DO functions such as I / O card combination of products, a independent dedicated system based on embedded PC technology, suitable for small SCADA system. Such as ICP DAS I-8000 series, the hosts within a 40MHz frequency 80188 CPU, operating system compatibility DOSMiniOS7, the programming environment is based on PC standard C language programming, and PLC program development process is very similar: first,BD ring sampling time and system stability. In general, an I-8000 module, usually not more than two such as I-8017H Series AI module better.
2.2 Relay Output module relay output module <BR> greatest impact on the entire system, not handled properly, will cause the entire system crashes and often crash, motherboard burnout phenomena, I-8000 module power supply is usually 10 ~ 30VDC, total input power of 20W, unlike the IPC input power is 250W so great, especially the high-power relay output module relay module plug in too much, the system of energy supply shortage, will result in the output is not normal, control systems often malfunction, leading to system crashes, when the machine will lead to control board burned out, the system stability, security and reliability factors that keep many hidden dangers. In general, such as I-8060, I-8058, I-8063, I-8064, I-8065, I-8066, I-8068, I-8069 and so not more than two, especially I-8060, I- 8063, I-8064, I-8065, I-8069 is one the best of these power modules. More power to control relay system can be separated using ordinary optical digital input / output modules, such as I-8042 multi-level amplification principle of connection.
2.3 communications processing <BR> by the PC-Based PLC control system architecture is the most important link with the host computer for real-time data communication process, and this link is often the constraints of real time and stability factors, the data is prone to bottlenecks. PC usually Windows operating system, application process generally was computer interface and real-time display interface, but often real-time interactive interface and display interface design for the front window, data communications, analysis and storage is designed to run in the background, but the Windows and As a real-time operating system designed to preemptive, multitasking, operating system based on message passing, but they alone ?????? scheduling mechanism, clearly can not meet the real-time system Yaoqiu, difficult to ensure the accurate real time before the completion of8, to absorb the spike. At the same time to separate signal and power supply.
2) Inverter over voltage processing: The system used a large inertial drag traction motor inverter, inverter output speed is faster, but slow down the load resistance by itself is relatively slow, dragging the motor speed of the load than the output frequency to the corresponding speed is even higher, the motor in generator mode, the converter unit without energy feedback, tributaries DC converter circuit voltage increased beyond the conservation value, over-voltage fault occurs. Regenerative braking unit must be increased, otherwise it will interfere with SCADA systems.
3.3 System Function 1) data: for each fuel as a number, bar graph, the curve displayed in real-time acquisition flow, temperature, switch status, motor speed and other parameters;
2) The flow and volume can be calculated to generate daily, monthly, annual reports, etc.; can store years of history;
3) to maintain data recovery: data loss with the parameter settings and repair.
4) The company s MIS systems with real-time exchange of data
4 Conclusions PC-Based PLC benefit from the development of embedded CPU, embedded operating system and IEC-61131-3 (LD, SFC, FBD, IL, ST) standardization of programming languages, PC-Based PLC has dual characteristics of IPC and PLC with PLC system architecture, but also has the IPC open architecture, the present industrial sector is IPC, PLC and PC-Based PLC coexistence of the times, gradually moving toward integration is three times, embedded CPU, embedded operating system and meet the IEC- 61131-3 international standard language development tools, development, PC-Based PLC or embedded controller will be more open and standardized features will become more powerful, data communication will be stronger, faster data processing capabilities. Can adapt to the more complex needs of industrial control.