1、 英文英文资料资料翻译翻译 题 目 Programmable Logic Controllers (PLC) 院 别 专 业 机电一体化技术 班 级 学生姓名 学 号 指导教师 2012 年 4 月 1 Programmable Logic Controllers (PLC)Programmable Logic Controllers (PLC) 1、Motivation Programmable Logic Controllers (PLC), a computing device invented by Richard E. Morley in 1968, have been widely
2、 used in industry including manufacturing systems, transportation systems, chemical process facilities, and many others. At that time, the PLC replaced the hardwired logic with soft-wired logic or so-called relay ladder logic (RLL), a programming language visually resembling the hardwired logic, and
3、 reduced thereby the configuration time from 6 months down to 6 days Moody and Morley, 1999. Although PC based control has started to come into place, PLC based control will remain the technique to which the majority of industrial applications will adhere due to its higher performance, lower price,
4、and superior reliability in harsh environments. Moreover, according to a study on the PLC market of Frost and Sullivan 1995, an increase of the annual sales volume to 15 million PLCs per year with the hardware value of more than 8 billion US dollars has been predicted, though the prices of computing hardware is steadily dropping. The inventor of the PLC, Richard E Morley, fairly considers the PLC market as a 5-billion industry at the present time. Tho
