关于plc的外文及翻译-plc设计(编辑修改稿)

关于plc的外文及翻译-plc设计(编辑修改稿)内容摘要：

many manufacturers offer at least two of these languages as options for programming their PLCs. Ironically, approximately 96 percent of PLC users recently still use ladder diagrams to construct their PLC code. It seems that ladder logic continues to be a top choice given it39。 s performed so well for so long. Hardware Platforms The modern PLC has incorporated many types of Commercial off the Shelf (COTS) technology in its CPU. This latest technology gives the PLC a faster, more powerful processor with more memory at less cost. These advances have also allowed the PLC to expand its portfolio and take on new tasks like munications, data manipulation and highspeed motion without giving up the rugged and reliable performance expected from industrial control equipment. New technology has also created a category of controllers called Programmable Automation Controllers, or PACs. PACs differ from traditional PLCs in that they typically utilize open, modular architectures for both hardware and software, using de facto standards for work interfaces, languages and protocols. They could be viewed as a PC in an industrial PLClike package. The Future A 2020 PLC Product Focus Study from Reed Research Group pointed out factors increasingly important to users, machine builders and those making the purchasing decisions. The top picks for features of importance were. The ability to work, and do so easily. Ether munications is leading the charge in this realm. Not only are new protocols surfacing, but many of the industry de facto standard serial protocols that have been used for many years are being ported to Ether platforms. These include Modbus (ModbusTCP), DeviceNet (Ether/IP) and Profibus (Profi). Ether munication modules for PLCs are readily available with highspeed performance and flexible protocols. Also, many PLC CPUs are now available with Ether ports on board, saving I/O slot space. PLCs will continue to develop more sophisticated connectivity to report information to other PLCs, system control systems, data acquisition (SCADA) systems and enterprise resource planning (ERP) systems. Additionally, wireless munications will continue to gain popularity. 4 The ability to work PLC I/O connections with a PC. The same trends that have benefited PLC working have migrated to the I/O level. Many PLC manufacturers are supporting the most accepted fieldbus works, allowing PLC I/O to be distributed over large physical distances, or located where it was previously considered nearly impossible. This has opened the door for personal puters to interface with standard PLC I/O subsystems by using interface cards。