关于控制系统中的PLC的选型方法外文文献翻译、中英文翻译、外文翻译

重 庆 理 工 大 学 文 献 翻 译 二级学院 班 级 学生姓名 学 号 关于控制系统中的 PLC 的选型方法 摘要 ：在设计关于 PLC 的控制系统时，首先应确定该系统的控制方案，然后下一步工作是为该工程设计选择 PLC 的型号。该控制系统运行过程中的特点和应用需求是 PLC 选型的主要依据。 PLC 和相关设备应该根据综合、标准、以及容易形成一个整体的工业控制系统和易扩展其功能的原则选择器件的类型，所选择的 PLC 应在相关工业领域的有成功的应用成果、该 PLC 在控制系统中有成熟和可靠的运用制度，该 PLC 的硬件、软件配置和功能都可适应安装的规模和控制要求。在设计该系统时知道它所使用的编程控制器，以及它的功能图像及相关的编程语言有利于缩短编程时间，因此，在选择该类型的项目设计和估算时，应先分析该项目的运行过程特点和控制要求，详细地明确该项目的控制任务和范围，根据操作和运动的要求，估算出输入和输出的数量、估计出存 储器容量、测定功能的大小以及外部设备性能等，最后选择具有较高的性价比的 PLC 和相应的控制系统设计。 随着 PLC 在工业控制系统中的普及， PLC 的数量和种类越来越多，功能也日趋完善。近年来，刚刚介绍的 PLC 产品已有自美国、日本和德国以及国内厂家组装或独立发展成型，已有几十种系列，几百种型号。 PLC 的类型众多，它的结构模型，性能、能力、指令系统和编程方法等各有不同，应用场合也各有不同。因此，在自动控制系统中合理的选择 PLC 的型号有很重要的作用。 随着科技的不断进步， PLC 的种类是越来越多，其功能也在逐渐增加强。虽 然本文总结了一些选择的方法，以及运用实例说明如何使用 PLC，但在实际工作中它还必须做出适当的调整。需要根据实际条件来用 PLC 设计工业控制系统，满足期望。 关键词 ： PLC；选型；控制系统 1、 介绍 PLC 的技术随着 计算机和微电子技术的发展而得到迅速发展。从开发出第一台PLC 后， 随着 CPU 的应用和单片机技术在 PLC 中的应用 ,形成现代意义上的第一台PLC。自 80年代到 20世纪的第一个十年 ,随着微电子技术的大跃进，出现了大规模集成电路和超级大型微电子技术， 16通道和 32通道的微处理器的出现 PLC 得到了惊人的开发 ,这使 得 PLC 在 概念、设计、性价比以及应用上获得了新的突破，不仅控制功能增强 ,功耗和体积减少 ,成本下降 ,可靠性上升 ,编程和故障检测更加灵活和方便 ,同时远程通信网络、数据处理以及人机界面 (HMI)也得到了快速的发展。现在 ,PLC 不仅可以应用于自动化生产行业 ,而且可以在连续生产时用于过程控制系统 ,这些使得它在自动化技术领域成为三大支柱之一 ,即使总线技术变成了今天的自动化技术应用的热点、但 PLC 在现场总线系统中仍是不可或缺的控制器。 总的来说，随着 PLC 在自动化工业控制系统中的发展和普及， PLC 的种类是越来越多，使用也 越来越广泛，因此合理选择 PLC，对提高自动控制系统在工作中的运用具有重要的作用。 2、 选择模型 我国的市场流行的 PLC 产品的生产厂家有以下几个公司： 1） 施耐德公司 ，包括引进自 Modicon 公司由早期天津仪器仪表厂生产的产品，现在的产品有 Quantum, Premium 和 Momentum； 2）罗克韦尔公司（包括 AB 公司） PLC 产品，现在的产品有 SLC、 Micro Logix 和 Control Logix 等 ； 3）西门子公司的 PLC 产品，现在的产品有 S7 - 400/ 300/ 200等系列； 4）通用电气公司 PLC 产品； 5）日本公司的产品如欧姆龙，三菱，富士，松下，其中最受欢迎的是三菱公司的 FX 系列。 PLC 选型的基本原理的 是 :在输入 /输出数量 满足要求的前提下应选择最可靠、维护和使用最方便以及性价比最优的产品。 3、 输入 /输出选择 PLC是一种工业控制系统 ,其控制对象是工业生产设备或工业产品生产过程、工作环境是工业生产现场。它连接的工业生产过程是通过 I/ O接口模块实现。 PLC有很多 I / O接口模块包括开关量输入模块、开关量输出模块、模拟量输入模块和模拟量输出模块以及一些特殊的模块 ,使用时 ,我 们应该根据他们的特征执行选项。 1）确定输入 /输出数量 根据控制系统的需求，确定所需输入 /输出的数量，应增加备用量的 10% - 20%，为了能在任何时间增加控制功能。 2）开关量输入 /输出 开关量输入 /输出接口可以从传感器和开关和控制设备接受信号。典型的交流输入 /输出信号 24-240V，直流输入 /输出信号 5-240V。 3）模拟量输入 /输出 模拟量输入 /输出接口可以接受由传感器产生的信号。这些接口可以用于测量流动率、温度和压力，并以此来控制由电压或电流的输出设备。这些接口的量程为 -10-+ l0v、 0-l0v、 4-20mA 或 10-50mA。 有些厂家在 PLC 上设计了特殊的专用模拟接口，因此它可以接收低电平信号。一般来说，这种接口模块可以用于接收不同类型的热电偶或 RTD 混合信号。 4）特殊功能输入 /输出 当选择一个 PLC，用户可能面临一些特殊类型的输入 /输出还有一些因为有限的输入 /输出的位置和快速响应以及频率问题造成的非标准的输入 /输出。现在，用户应该考虑是否接受由市场或制造商提供的专用模块，通过专用模块自行处理一部分的数据，从而减少 CPU 的使用，提高任务处理的效率，以最大限度降低因高温限制造成的控制失灵。 5）智能输入 /输出 目前， PLC 厂家制造出了一些智能输入输出连续模块。一般智能输入 /输出模块可以自我处理，它可以对指定的输入或输出信号做出提前处理，并将结果传送到 CPU 或直接输出，因此可以提高处理速度和节省存储容量。 智能输入 /输出模块有高速计数器， cam 模拟器、凸轮模拟器速度补偿、单回路或者倍增 PID 调节器、 ASCII/BASIC 处理器和 RS - 232 C / 422接口模块等。 PLC 的输入 /输出模块的一般选择原则：根据设备现场或操作选择的类型和数量来选择 I/O 模块。 4、 选择类型和存储容量 PLC 所使用的内存的系统主要是有 3种： EPROM， ROM 和 RAM。内存的容量的大小一般与 PLC 的大小有关，通常小型机的最大的存储能力要小于 6kb，中型机器的最大存储能力可以达到 64KB，而大型机的最大存储能力可达到兆字节。使用时可以根据程序和数据存储能力选择适合的类型，必要时也可以进行内存扩大设计。 PLC 中内存的选择方法：根据编程所用的节点数来准确计算实际所需内存的容量。 5、 软件选择 在系统的实现过程中， PLC 的编程问题是非常重要的。用户应该知道 PLC 产品的软件功能。通常，一个系统的软件是用来处理控制硬件的。但有 时一些应用系统除了需要控制硬件部分外还需要软件的一些功能。 一个程序块由可执行代码和注释组成。可执行代码由主程序和若干子程序或者中断服务程序组成。可执行代码被编译并下载到 FX2N 中，而程序注释不会被下载。您可以使用组织组件（主程序、子程序和中断服务程序）来结构化您的控制程序。 主程序 主程序中包括控制应用的指令。 FX2N 在每一个扫描周期中顺序执行这些指令。 子程序 子程序是应用程序中的可选组件。只有被主程序、中断服务程序或者其它子程序调用时，子程序才会执行。当您希望重 复执行某项功能时，子程序是非常有用的。与其在主程序中的不同位置多次使用相同的程序代码，不如将这段程序逻辑写在子程序中，然后在主程序中需要的地方调用。调用子程序有如下优点： (1)用子程序可以减小程序的长度。 (2)由于将代码从主程序中移出，因而用子程序可以缩短程序扫描周期。 FX2N在每个扫描周期中处理主程序中的代码，不管代码是否执行。而子程序只有在被调用时， FX2N 才会处理其代码。在不调用子程序时， FX2N 不会处理其代码。 (3)用子程序创建的程序代码是可传递的。您可以在一个子程序中 完成一个独立的功能，然后将它复制到另一个应用程序中而无需作重复工作。 中断服务程序 中断服务程序是应用程序中的可选组件。当特定的中断事件发生时，中断服务程序执行。您可以为一个预先定义好的中断事件设计一个中断服务程序。当特定的事件发生时， FX2N 会执行中断服务程序。中断服务程序不会被主程序调用。只有当中断服务程序与一个中断事件相关联，且在该中断事件发生时， FX2N 才会执行中断服务程序。 提示：因为无法预测何时会产生中断，所以应考虑尽量限制中断服务程序和程序中其它部分所共用的变量个数。使 用中断服务程序中的局部变量，可以保证中断服务程序只使用临时存储器，并且不会覆盖程序中其它部分使用的数据。为了保证主程序与中断服务程序正确地共享数据，您可以使用许多编程技巧。 6、 结论 随着科技的不断进步， PLC 的种类是越来越多，功能也逐渐增强。在文章中，虽然有总结一些选择的方法，但在实际工作中我们仍然必须做出适当的调整，根据实际情况来设计控制系统以满足期望。 原文： The Method Selecting Type of PLC in Controlling System Abstract: When designing PLC system,first determining control scheme, the work of next step is PLC selecting type of project design. The characteristic of process and application requirement are the major accordance of designing selecting type.PLC and relevant equipments should be integrated、 standard 、 according to the principle easy to form a whole with industrial control system and easy to expand its function to select type, PLC chosen should have application achievement in related industrial field 、 the maturation and reliable system,the systematic hardware 、 software configuration and function of PLC should suit with installation scale and control requirement.Knowing programming controller, function picture and relevant programming language is helpful to shorten programming time. Therefore, selecting type of project design and estimating, it should analyse the characteristic of process and control requirement in detail, definite control task and range, determing operation and movement required,then according to control ask to estimate numbers of inputs and outputs、 memory capacity required、 determing function of PLC, the external equipment property etc. finally selecting having higher price performance PLC and desigin g the corresponding control system. Along with popularization of PLC in industrial control, quantity and kind of PLC product are more and more and function also becomes perfect day by day. In recent years, the PLC products that introduced from the countries such as America、 Japan and Germany and the domestic manufacturer assembles or develops independently have had tens of series, hundreds of models. The kind of PLC is numerous, its structural model , performance、 capacity、 instruction system and programming method etc are different, application occasion has also each to stress. Therefore, select PLC reasonably, the application for PLC in control system has important role. Along with the unceasing advance of science and technology, the kind of PLC is increasingly numerous,its function also strengthens gradually. Though the article have sumed up some methods of choosing PLC and exampled to explain how to use, in practical work it must still make proper adjustment according to practical condition in order to design the industrial control system that satisfies expectation. Key words: PLC； selecting type； controlling system I. Introduction PLC technology develops promptly along with the development of computer and microelectronics technology, and develops from a initial machine to 8 machines. Along with application of microprocessor CPU and the technical of microcomputer in PLC, it has formed PLC on modern meaning. Since 80 decade of 20 century, along with microelectronics technology development of the large-scale and super large-scale Integrated circuit etc. microelectronics technology, That the 16 and 32 microprocessor forms microcomputer PLC have gotten astonishing development, these make PLC get new breakthrough in the aspects such as concept、 design、 price performance as well as application. Not only control function strengthens, power consumption and volume reduce, cost drops, reliability rises, programming and fault detection are more flexible and convenient, but also long-range UO and communication network, data handling as well as man-machine interface (HMI) also have got rapid development. Now, PLC can not only apply in the automation of manufacturing industry but also can still apply in the course control system in serial production, these have made it become one of 3 pillar in automation technical field, even if the technology of bus line becomes today of automation technical application hot point, PLC is still the indispensable controller in the control system on-the-spot of bus line. Synthesized, along with the development of PLC and its popularize in automation industrial control, the kind of PLC product is more and more and use is also more and more extensive, therefore, selecting PLC reasonably for raising the application of PLC in control system has important role. II. Selecting machine model The market of our country has the popular PLC product that has following few company: 1) Schneider company, include early Tianjin instrument and meter plant transfer the product of Modicon company, now, there is the products such as Quantum, Premium and Momentum； 2) Rockwell company (include AB company) PLC product, now, there is the products such as SLC、 Micro Logix and Control Logix； 3) Siemens company product, now, there is S7-400/300/200 series products； 4) GE company product； 5) Japan companys products such as Omron,Mitsubishi, Fuji and Panasonic, in which used more is FX series of Mitsubishi company. The basic principle of PLC type option is: under function satisfies the prerequisite of requirement to select type of most reliable, maintenance and use most facilitate as well as the price performance optimization. III. Selecting I/O PLC is a kind of industrial control system, its control object is industrial production equipment or industrial production course, working environment is industrial production scene. Its connections with industrial production course realize through the I/O interface module. PLC has a lot of I/O interface module including switch quantity input module、 switch quantity export module, simulated quantity input module and simulated quantity export module as well as some special module, when using, we should carry out option according to their characteristic. 1) Determine I/O numbers According to control systematic requirement to determine I/O numbers needed, it should increase the spare quantity of 10%-20%, in order to increase control function at any time. 2) Switch quantity I/O The switch quantity I/O interface can take over signal from sensor and switch and control equipment.Typical AC I/O signal is 24-240V, the DC I/O signal is 5-240V. 3) Simulated quantity I/O The simulated quantity I/O interface normally perceives the signal that sensor produces. These interfaces can be used to measure rate of flow、 temperature and pressure, and used in controlling voltage or current export equipment. the typ ical span of these interfaces is-10-+ l0V、 0-+l0V、 4-20mA or 10-50mA. Some manufacturers in PLC design special simulated interface, thus it can take over low level signal. Generally speaking, this kind of interface module can be used to take over the different type of thermocouple or RTD mix signal. 4) Special function I/O When selecting a PLC, user may faced some special types and cant be realized by standard I/O as the limited position I/O, fast input and frequency etc. Right now, user should consider whether supply and market manufacturer offers the special module that is helpful for high limit to reduce control role, some special interface modules selves can handle a part of field data and make CPU free from the consuming task handling. 5) Intelligent I/O Currently, PLC manufacturers protrude some intelligent I/O modules in succession. Generally the intelligent I/O module self has with processor, it can assigned handling for inputting or exporting signal in advance, and will send result to CPU or output directly, so this can raise the handling speed of PLC and save the capacity of memory. Intelligent I/O has the high speed counter, cam simulator、 the cam simulator with speed compensation、 single loop or multiply loop PID regulator、 the ASCI1/BASIC processor and RS-232C/422 interface module etc. The general principle of selecting the I/O module is: According to equipment on-the-spot or the operating to select the type and count of the 1l0 module. IV. Selecting type and capacity of memory The memory used by PLC system basically is composed from 3 kinds of type as PROM, EPROM and RAM, memory capacity changes with the size of machine, normally the biggest store ability of small-sized machine is lower than 6KB, the biggest store ability of medium-sized machine can reach 64KB, the biggest store ability of large scale machine can reach MB. When using we can choose suitable type according to program and data store capacity and can also carry out memory expand design especially necessarily. The option method of memory capacity: According to the node that programming uses to calculate accurately the actual use capacity of memory. V. Selecting software In the course of systematic realizing, the programming problem of PLC is very important. User should know as software function of PLC product. Usually, a systematic software is used in handling the control hardware that controller has always. But some application systems need also the software function besides controlling hardware parts. A program block is composed of executable code and comments. The executable code consists of a main program and any subroutines or interrupts routines. The code is compiled and downloaded to the FX2N； the program comments are not. You can use the organizational elements (main program, subroutines, and interrupt routines) to structure your control program. Main Program The main body of the program contains the instructions that control your application. The FX2N executes these instructions sequentially, once per scan cycle. Subroutines These optional elements of your program are executed only when called: by the main program, by an interrupt routine, or by another subroutine. Subroutines are useful in cases where you want to execute a function repeatedly. Rather than rewriting the logic for each place in the main program where you want the function to occur, you can write the logic once in a subroutine and call the subroutine as many times as needed during the main program. Subroutines provide several benefits: (1)Using subroutines reduces the overall size of your program. (2)Using subroutines decreases your scan time because you have moved the code out of the main program. The FX2N evaluates the code in the main program every scan cycle, whether the code is executed or not, but the FX2N evaluates the code in the subroutine only when you call the subroutine, and does not evaluate the code during the scans in which the subroutine is not called. (3)Using subroutines creates code