PLC中英文翻译.doc

PLC今天的PLC（可编程逻辑控制器）将面对日益复杂的挑战。一旦他们悄悄地取代继电器，偶尔向主机报告，如果他们将他们比作细胞，赋予新的工作和新的语言，将被迫和大量的控制产品竞争。对于今年的年度PLC技术的更新，我们对PLC的制造商会就这些主题提出更多问题。编程语言更高水平的PLC编程语言已经推行有一段时间了，但最近的流行，如雨后春笋般。正如雷蒙德莱韦耶，副总裁兼总经理，西门子能源和自动化公司，可编程控制正在为更复杂的操作使用，梯形逻辑比语言变得更加实际，有效和强大的。举例来说，很难写三角函数使用梯形逻辑。“语言为人们所接受，包括布尔，控制系统流程图，这种功能图及其变化图表语言。而且有越来越多像C和BASIC语言的兴趣。”在过程的PLC控制到目前为止，PLC的没有大量用于连续过程控制，会继续吗？“我感觉到了，PLC将用于过程工业，但不一定过程控制。” Jannotta说。 几个供应商，显然是把赌注押在相反会发生，已经实行了PLC的应用优化的过程。富瑞安的经理认为PLC将越来越多地使用食品等行业，化工，石化.Ryan认为有两种类型的应用程序中，他们是合适的。“之一，”他说，“是其中的过程控制系统，目前已被没有理由自动化DCS的大小分布式控制系统随着价格标签开始。产品的选择是比较高，可编程控制器为小，低环数的应用意义。第二种是你必须融入顺序逻辑。批次控制循环密切合作是最好的例子，那里的顺序和维持过程变量是交织在一起的密切合作，使拥有一个可编程控制器的逻辑顺序做的好处远远超过了不具有分布式控制系统的一些缺点。”Bill Barkovitz， Triconex的总统，预言：“今后所有的控制器在过程控制系统的业务将引用更多的PLC技术， PLC功能比以往任何时候都要多。”通信和规范在整体上通信是至关重要的个人自动化单元对自动化工厂来说。我们听说了很多规范在过去数年，许多公司都纷纷跟进。但是，不少人失望的发现完成地图规范并没有立即出现。拉里科马雷克说：“现在，规范仍然是一个移动目标，规范没有最终决定，对于制造商。目前，正在推出的产品样本.人们使其产品满足MAP2.1标准。然而，新标准MAP3.0被引进时，MAP2.1为基础的产品将被淘汰时。”正因为如此，许多PLC厂商正在制定完整的规范. 例如Omron，拥有一个完整的兼容程序，但弗兰克纽伯恩，副欧姆龙工业部总裁，报告说，由于缺乏公司的定义，欧姆龙的PLC还谈不上规范。 由于不太可能将个人的PLC广泛的交谈，制造商更专注于专有的网络.按照萨尔Provanzano说法，用户担心，如果他们不从规则上和供应商妥协，他们将要加大对通信结构的不支持。通用的I/O然而大多数PLC的兼容问题不同厂商的沟通不够，在另一端连接的I/O问题，更是支离破碎的。除了少数例外，I/O是仍然专有技术。然而，谁是那些感觉的I/O最终将成为更具有普遍性。GE Fanuc的希望这样做与天才智能I/O线.各个独立I/O制造商都在同一方向进发。许多人说，I/O是这样一个高价值项目， PLC制造商将永远希望保持它的专有性。由于肯Jannotta。说：“ I/O将在硬件销售中不成比例。当然每个PLC供应商将试图保护这一点。”出于这个原因，他说，PLC的制造商将不会开始销售通用I/O和其他厂商的系统。“如果我们开始销售该产品的实物，那我们还有什么可生产的？” Jannotta说道随着更多智能I/O出现，萨尔Provanzano认为在不同的制造商中间这将导致更多的分化。“哪里的I/O变得非常聪明，并成为系统的一部分真的很难定义，哪些是I/O，哪些是CPU.随着分布式的发展，如果你愿意，CPU也同样可以纳入作为I/O的系统”PLC的 I/O和个人电脑的连接虽然不同的PLC厂商可能会继续用专有的I/O，但一些厂商使I/O连接到IBM PC这样的兼容设备成为可能.Alle - bradeley和辛辛那提米拉克龙公司已经拥有，并有传言说，通用的电气计划将沿着同样的思路。克特尔胡特， GE Fanuc北美的产品规划经理，认为是I/O的普及“我想多个主机接口将代替I/O的趋势，”他说。朱迪格洛尔，市场经理，Square D Automation Products，将PLC看做是工业电脑。PLC和电脑如果IBM 7552，行动仪器BC22，和其他计算机出现在工厂，这意味着不会对PLC的新的竞争？富瑞安：“有一些控制功能，可用于电脑.可编程程序控制器更好的工作已被迫适应这些应用。“然而，在我们调查的厂商多数不认为“个人电脑入侵”将对他们产生问题。大多表示PLC和PC结构上的差别决定他们不同的作用，PC将主管通讯和管理，PLC则进行控制，他们相信这只是意味着，PLC和个人电脑将能够共享相同的数据。富瑞恩说：“通用的计算机内在结构不同，可编程控制器硬件结构有内置到几乎每一个制造商的可编程控制器。今天定制的硬件来运行梯形逻辑，解决机器代码。”在根本的区别上，他引用了一个称呼“机器状态”。富瑞安说：“当你关闭机器，或中断周期，或者跳转到另一个周期，现场可编程控制器本身记得机器的状态：定时器状态是什么，计数器状态是什么，锁存的状态是什么,但计算机本身不这样做。”PLCPLCs (programmable logical controller) face ever more complex challenges these days . Where once they quietly replaced relays and gave an occasional report to a corporate mainframe, they are now grouped into cells, given new job and new languages, and are forced to compete against a growing array of control products. For this years annual PLC technology update ,we queried PLC makers on these topics and more .Programming languages Higher level PLC programming languages have been around for some time ,but lately their popularity has mushrooming. As Raymond Leveille, vice president & general manager, Siemens Energy &Automation .inc; Programmable controls are being used for more and more sophisticated operations, languages other than ladder logic become more practical, efficient, and powerful. For example, its very difficult to write a trigonometric function using ladder logic .Languages gaining acceptance include Boolean, control system flowcharting, and such function chart languages as Graphcet and its variation .And theres increasing interest in languages like C and BASIC.PLCs in process controlThus far, PLCs have not been used extensively for continuous process control .Will this continue? The feeling that Ive gotten, says Ken Jannotta, manger, product planning, series One and Series Six product ,at GE Fanuc North America ,is that PLCs will be used in the process industry but not necessarily for process control.Several vendors -obviously betting that the opposite will happen -have introduced PLCs optimized for process application .Rich Ryan, manger, commercial marketing, Allen-bradley Programmable Controls Div., cites PLCss increasing use such industries as food ,chemicals ,and petroleum. Ryan feels there are two types of applications in which theyre appropriate. one, he says, is where the size of the process control system thats being automated doesnt justify DCSdistributed control system.With the starting price tags of chose products being relatively high, a programmable controller makes sense for small, low loop count application .The second is where you have to integrate the loop closely with the sequential logical .Batch controllers are prime example ,where the sequence and maintaining the process variable are intertwined so closely that the benefits of having a programmable controller to do the sequential logical outweighs some of the disadvantages of not having a distributed control system.Bill Barkovitz, president of Triconex, predicts that all future controllers that come out in the process control system business will embrace a lot of more PLC technology and a lot more PLC functionality than they ever did before .Communications and MAPCommunications are vital to an individual automation cell and to be automated factory as a whole. Weve heard a lot about MAP in the last few years ,and a lot of companies have jumped on the bandwagon.Many, however, were disappointed when a fully-defined and completed MAP specification didnt appear immediately .Says Larry Komarek: Right now, MAP is still a moving target for the manufacturers, a specification that is not final .Presently, for example. people are introducing products to meet the MAP2.1standard .Yet2.1-based products will be obsolete when the new standard for MAP3.0 is introduced.Because of this, many PLC vendors are holding off on full MAP implementations. Omron, for example, has an ongoing MAP-compatibility program;but Frank Newburn, vice president of Omrons Industrial Division ,reports that because of the lack of a firm definition ,Omrons PLCs dont yet talk to MAP.Since its unlikely that an individual PLC would talk to broad MAP anyway, makers are concentrating on proprietary networks. According to Sal Provanzano, users fear that if they do get on board and vendors withdraw from MAP, theyll be the ones left holding a communications structure thats not supported.Universal I/OWhile there are concerns about the lack of compatible communications between PLCs from different vendors, the connection at the other end-the I/O-is even more fragmented .With rare exceptions, I/O is still proprietary .Yet there are those who feel that I/O will eventually become more universal .GE Fanuc is hoping to do that with its Genius smart I/O line. The independent I/O makers are pulling in the same direction. Many say that I/O is such a high-value item that PLC makers will always want to keep it proprietary .As Ken Jannotta, says: The I/O is going to be a disproportionate amount of the hardware sale. Certainly each PLC vendor is going to try to protect that. For that reason, he says, PLC makers wont begin selling universal I/O system from other vendor. if we start selling that kind of product, says jannotta, what do we manufacture?With more intelligent I/O appearing, Sal Provanzano feels this will lead to more differentiation among I/O from different makers. Where the I/O becomes extremely intelligent and becomes part of the system, he says, it really is hard to define which is the I/O and which is CPU. It really CPU, if you will, is equally integrated into the system as the I/O.Connecting PLC I/O to PCsWhile different PLCs probably will continue to use proprietary I/O, several vendors make it possible to connect5 their I/O to IBM PC-compatible equipment. Alle-bradeley, Could, and Cincinnati Milacron already have, and rumor has it that GE is planning something along these same lines .Bill Ketelhut, manage of product planning at GE Fanuc North America ,sees this sort of thing as alternative to universal I/O.I think the trend ,instead of toward universal I/O, will be multiple host interface , he says .Jodie Glore ,director of marking, Square D Automation Products, Views it as another indication that PLCs are, and have been for some time, industrial computers.PLCs and PCsIf the IBM 7552, the Action Instruments BC22,and other computers are appearing on the factory floor, wont this mean new competition for PLCs? Rich Ryan: There are some control functions that are better jobs for computers. Programmable controllers have been forced to fit into those applications. Yet, the majority of vendors we surveyed dont like the PC invasion will pose a problem for them .Most said that PLCs and P