1、 青岛理工大学 外文翻译 题目 Programmable Logic Controller 学生姓名： 郭军义 指导教师： 田艳兵 自动化工程 学院 电气工程及其自动化 专业 082 班 2012 年 6 月 12 日 青岛理工大学毕业设计（论文）外文翻译 目 录 Programmable Logic Controller (PLC) . 1 1. About Programmable Logic Controller (PLC) . 1 2. INTRODUCTION . 2 3. OPERATION SEQUENCE . 4 3 .1 The Input and Output Scans
2、. 5 3.2 The Logic Scan . 5 4 PLC STATUS . 6 5. MEMORY TYPES . 7 6. SOFTWARE BASED PLCS . 8 7. SUMMARY . 8 8. PRACTICE PROBLEMS . 8 9. PRACTICE PROBLEM SOLUTIONS . 9 中文翻译 . 11 1. PLC 介绍 . 11 2指令 . 12 3运行顺序 . 13 3.1 输入输出扫描 . 14 3 2 逻辑扫描 . 14 4 PLC 状态显示 . 15 5存储器类型 . 16 6基于软件的 PLC 系统 . 16 7概要 . 17 8实际问
3、题 . 17 9实际问题解答 . 17 青岛理工大学毕业设计（论文）外文翻译 1 Programmable Logic Controller (PLC) 1. About Programmable Logic Controller (PLC) PLC (programmable logic controllers) is the control hubs for a wide variety of automated systems and processes. They contain multiple inputs and outputs that use transistors and
4、other circuitry to simulate switches and relays to control equipment. They are programmable via software interfaced via standard computer interfaces and proprietary languages and network options. Programmable logic controllers I/O channel specifications include total number of points, number of inpu
5、ts and outputs, ability to expand, and maximum number of channels. Number of points is the sum of the inputs and the outputs. PLC may be specified by any possible combination of these values. Expandable units may be stacked or linked together to increase total control capacity. Maximum number of cha
6、nnels refers to the maximum total number of input and output channels in an expanded system. PLC system specifications to consider include scan time, number of instructions, data memory, and program memory. Scan time is the time required by the PLC to check the states of its inputs and outputs. Inst
7、ructions are standard operations (such as math functions) available to PLC software. Data memory is the capacity for data storage. Program memory is the capacity for control software. Available inputs for programmable logic controllers include DC, AC, analog, thermocouple, RTD, frequency or pulse, t
8、ransistor, and interrupt inputs. Outputs for PLC include DC, AC, relay, analog, frequency or pulse, transistor and triac. Programming options for PLC include front panel, hand held and computer. Programmable logic controllers use a variety of software programming languages for control. These include
9、 IEC 61131-3, sequential function chart (SFC), function block diagram (FBD), ladder diagram (LD),structured text (ST), instruction list (IL), relay ladder logic (RLL), flow chart, C, and Basic. The IEC 61131-3 programming environment provides support for five languages specified by the global standa
10、rd: Sequential Function Chart, Function Block Diagram, Ladder Diagram, Structured Text, and Instruction List. This allows for multi-vendor compatibility and multi-language programming. SFC is a graphical language that provides coordination of program sequences, supporting alternative sequence selections and parallel
