关于plc的外文文献翻译中英文翻译外文翻译

2024年2月4日发(作者：)

外文资料译文

PLC technique discussion and future development

Along with the development of the ages, the technique that is nowadays is

also gradually perfect, the competition plays more strong; the operation that

list depends the artificial has already can't satisfied with the current

manufacturing industry foreground, also can't guarantee the request of the

higher quantity and high new the image of the technique business enterprise.

The people see in produce practice, automate brought the tremendous

convenience and the product quantities for people up of assurance, also eased

the personnel's labor strength, reduce the establishment on the personnel. The

target control of the hard realization in many complicated production lines,

whole and excellent turn, the best decision etc., well-trained operation work,

technical personnel or expert, governor but can judge and operate easily, can

acquire the satisfied result. The research target of the artificial intelligence

makes use of the calculator exactly to carry out, imitate these intelligences

behavior, moderating the work through person's brain and calculators, with the

mode that person's machine combine, for resolve the very complicated

problem to look for the best path

PLC language is not we imagine of edit collected materials the language

or language of Cs to carry on weaving the distance, but the trapezoid diagram

that the adoption is original after the electric appliances to control, make the

electrical engineering teacher while weaving to write the procedure very easy

comprehended the PLC language, and a lot of non- electricity professional also

very quickly know and go deep into to the PLC.

Is PLC one of the advantage above and only, this is also one part that the

people comprehend more and easily, in a lot of equipments, the people have

already no longer hoped to see too many control buttons, they damage not only

and easily and produce the artificial error easiest, small is not a main error

perhaps you can still accept; But lead even is a fatal error greatly is what we

can't is tolerant of. New technique always for bringing more safe and

convenient operation for us, make we a lot of problems for face on sweep but

light, do you understand the HMI? Says the HMI here you basically not clear

what it is, also have no interest understanding, change one inside text explains

it into the touch to hold or man-machine interface you knew, and it combines

with the PLC to our larger space.

When we are work a work piece, giving the PLC a signal, counting PLC

inner part the machine add 1 to compute us for a day of workload, a count the

machine and can solve problem in brief, certainly they also can keep the data

under the condition of dropping the electricity, urging the data not to throw to

lose, this is also what we hope earnestly.

The PLC still has the function that the high class counts the machine,

being us while accept some dates of high speed, the high speed that here say is

the data of the in all aspects tiny second class, for example the bar code

scanner is scanning the data continuously, calculating high-speed signal of the

data processor DSP etc., we will adopt the high class to count the machine to

help we carry on count. It at the PLC carries out the procedure once discover

that the high class counts the machine to should of interruption, will let go of

the work on the hand immediately. The trapezoid diagram procedure that

passes by to weave the distance again explains the high class for us to carry

out procedure to count machine would automatic performance to should of

work, thus rise the Class that the high class counts the machine to high one

Class.

You heard too many this phrases perhaps:" crash", the meaning that is

mostly is a workload of CPU to lead greatly, the internal resources shortage

etc. the circumstance can't result in procedure circulate. The PLC also has the

similar circumstance, there is a watchdog WDT in the inner part of PLC, we

can establish time that a procedure of WDT circulate, being to appear the

procedure to jump to turn the mistake in the procedure movement process or

the procedure is busy, movement time of the procedure exceeds WDT

constitution time, the CPU turn but the WDT reset the appearance. The

procedure restarts the movement, but will not carry on the breakage to the

interruption.

The PLC development has already entered for network ages of

correspondence from the mode of the one, and together other works control the

net plank and I/ O card planks to carry on the share easily. A state software

can pass all se hardwires link, more animation picture of keep the view to

carries on the control, and cans pass the Internet to carry on the control in the

foreign land, the blast-off that is like the absolute being boat is to adopt this

kind of way to make airship go up the sky.

The development of the higher layer needs our continuous effort to obtain.

The PLC emergence has already affected a few persons fully, we also obtained

more knowledge and precepts from the top one experience of the generation,

coming to the continuous development PLC technique, push it toward higher

wave tide.

Knowing the available PLC network options and their best applications

will ensure an efficient and flexible control system design.

The programmable logic controller's (PLC's) ability to support a range of

communication methods makes it an ideal control and data acquisition device

for a wide variety of industrial automation and facility control applications.

However, there is some confusion because so many possibilities exist. To help

eliminate this confusion, let's list what communications are available and

when they would be best applied.

To understand the PLC's communications versatility, let's first define the

terms used in describing the various systems.

ASCII: This stands for "American Standard Code for Information

Interchange." As shown in Fig. 1, when the letter "A" is transmitted, for

instance, it's automatically coded as "65" by the sending equipment. The

receiving equipment translates the "65" back to the letter "A." Thus, different

devices can communicate with each other as long as both use ASCII code.

ASCII module: This intelligent PLC module is used for connecting PLCs

to other devices also capable of communicating using ASCII code as a vehicle.

Bus topology: This is a linear local area network (LAN) arrangement, as

shown in Fig. 2A, in which individual nodes are tapped into a main

communications cable at a single point and broadcast messages. These

messages travel in both directions on the bus from the point of connection

until they are dissipated by terminators at each end of the bus.

CPU: This stands for "central processing unit," which actually is that part

of a computer, PLC, or other intelligent device where arithmetic and logical

operations are performed and instructions are decoded and executed.

Daisy chain: This is a description of the connection of individual devices

in a PLC network, where, as shown in Fig. 3, each device is connected to the

next and communications signals pass from one unit to the next in a sequential

fashion.

Distributed control: This is an automation concept in which portions of an

automated system are controlled by separate controllers, which are located in

close proximity to their area of direct control (control is decentralized and

spread out over the system).

Host computer: This is a computer that's used to transfer data to, or

receive data from, a PLC in a PLC/computer network.

Intelligent device: This term describes any device equipped with its own

CPU.

I/O: This stands for "inputs and outputs," which are modules that handle

data to the PLC (inputs) or signals from the PLC (outputs) to an external

device.

Kbps: This stands for "thousand bits per second," which is a rate of

measure for electronic data transfer.

Mbps: This stands for "million bits per second."

Node: This term is applied to any one of the positions or stations in a

network. Each node incorporates a device that can communicate with all other

devices on the network.

Protocol: The definition of how data is arranged and coded for

transmission on a network.

Ring topology. This is a LAN arrangement, as shown in Fig. 2C, in which

each node is connected to two other nodes, resulting in a continuous, closed,

circular path or loop for messages to circulate, usually in one direction. Some

ring topologies have a special "loop back" feature that allows them to continue

functioning even if the main cable is severed.

RS232. This is an IEEE standard for serial communications that describes

specific wiring connections, voltage levels, and other operating parameters for

electronic data communications. There also are several other RS standards

defined.

Serial: This is an electronic data transfer scheme in which information is

transmitted one bit at a time.

Serial port: This the communications access point on a device that is set

up for serial communications.

Star topology. This is a LAN arrangement in which, as shown in Fig. 2B,

nodes are connected to one another through a central hub, which can be active

or passive. An active hub performs network duties such as message routing

and maintenance. A passive central hub simply passes the message along to all

the nodes connected to it.

Topology: This relates to a specific arrangement of nodes in a LAN in

relation to one another.

Transparent: This term describes automatic events or processes built into

a system that require no special programming or prompting from an operator.

Now that we're familiar with these terms, let's see how they are used in

describing the available PLC network options.

PLC network options

PLC networks provide you with a variety of networking options to meet

specific control and communications requirements. Typical options include

remote I/O, peer-to-peer, and host computer communications, as well as LANs.

These networks can provide reliable and cost-effective communications

between as few as two or as many as several hundred PLCs, computers, and

other intelligent devices.

Many PLC vendors offer proprietary networking systems that are unique

and will not communicate with another make of PLC. This is because of the

different communications protocols, command sequences, error-checking

schemes, and communications media used by each manufacturer.

However, it is possible to make different PLCs "talk" to one another;

what's required is an ASCII interface for the connection(s), along with

considerable work with software.

Remote I/0 systems

A remote I/O configuration, as shown in Fig. 4A, has the actual inputs

and outputs at some distance from the controller and CPU. This type of system,

which can be described as a "master-and-slave" configuration, allows many

distant digital and analog points to be controlled by a single PLC. Typically,

remote I/Os are connected to the CPU via twisted pair or fiber optic cables.

Remote I/O configurations can be extremely cost-effective control

solutions where only a few I/O points are needed in widely separated areas. In

this situation, it's not always necessary, or practical for that matter, to have a

controller at each site. Nor is it practical to individually hard wire each I/O

point over long distances back to the CPU. For example, remote I/O systems

can be used in acquiring data from remote plant or facility locations.

Information such as cycle times, counts, duration or events, etc. then can be

sent back to the PLC for maintenance and management reporting.

In a remote I/O configuration, the master controller polls the slaved I/O

for its current I/O status. The remote I/O system responds, and the master PLC

then signals the remote I/O to change the state of outputs as dictated by the

control program in the PLC's memory. This entire cycle occurs hundreds of

times per second.

Peer-to-peer networks

Peer-to-peer networks, as shown in Fig. 4B, enhance reliability by

decentralizing the control functions without sacrificing coordinated control. In

this type of network, numerous PLCs are connected to one another in a

daisy-chain fashion, and a common memory table is duplicated in the memory

of each. In this way, when any PLC writes data to this memory area, the

information is automatically transferred to all other PLCs in the network. They

then can use this information in their own operating programs.

With peer-to-peer networks, each PLC in the network is responsible for

its own control site and only needs to be programmed for its own area of

responsibility. This aspect of the network significantly reduces programming

and debugging complexity; because all communications occur transparently to

the user, communications programming is reduced to simple read-and-write

statements.

In a peer-to-peer system, there's no master PLC. However, it's possible to

designate one of the PLCs as a master for use as a type of group controller.

This PLC then can be used to accept input information from an operator input

terminal, for example, sending all the necessary parameters to other PLCs and

coordinating the sequencing of various events.

Host computer links

PLCs also can be connected with computers or other intelligent devices.

In fact, most PLCs, from the small to the very large, can be directly connected

to a computer or part of a multi drop host computer network via RS232C or

RS422 ports. This combination of computer and controller maximizes the

capabilities of the PLC, for control and data acquisition, as well as the

computer, for data processing, documentation, and operator interface.

In a PLC/computer network, as shown in Fig. 4C, all communications are

initiated by the host computer, which is connected to all the PLCs in a

daisy-chain fashion. This computer individually addresses each of its

networked PLCs and asks for specific information. The addressed PLC then

sends this information to the computer for storage and further analysis. This

cycle occurs hundreds of times per second.

Host computers also can aid in programming PLCs; powerful

programming and documentation software is available for program

development. Programs then can be written on the computer in relay ladder

logic and downloaded into the PLC. In this way, you can create, modify, debug,

and monitor PLC programs via a computer terminal.

In addition to host computers, PLCs often must interface with other

devices, such as operator interface terminals for large security and building

management systems. Although many intelligent devices can communicate

directly with PLCs via conventional RS232C ports and serial ASCII code,

some don't have the software ability to interface with individual PLC models.

Instead, they typically send and receive data in fixed formats. It's the PLC

programmer's responsibility to provide the necessary software interface.

The easiest way to provide such an interface to fixed-format intelligent

devices is to use an ASCII/BASIC module on the PLC. This module is

essentially a small computer that plugs into the bus of the PLC. Equipped with

RS232 ports and programmed in BASIC, the module easily can handle ASCII

communications with peripheral devices, data acquisition functions,

programming sequences, "number crunching," report and display generation,

and other requirements.

Access, protocol, and modulation functions of LANs

By using standard interfaces and protocols, LANs allow a mix of devices

(PLCs, PCs, mainframe computers, operator interface terminals, etc.) from

many different vendors to communicate with others on the network.

Access: A LAN's access method prevents the occurrence of more than one

message on the network at a time. There are two common access methods.

Collision detection is where the nodes "listen" to the network and

transmit only if there are no other messages on the network. If two nodes

transmit simultaneously, the collision is detected and both nodes retransmit

until their messages get through properly.

Token passing allows each node to transmit only if it's in possession of a

special electronic message called a token. The token is passed from node to

node, allowing each an opportunity to transmit without interference. Tokens

usually have a time limit to prevent a single node from tying up the token for a

long period of time.

Protocol: Network protocols define the way messages are arranged and

coded for transmission on the LAN. The following are two common types.

Proprietary protocols are unique message arrangements and coding

developed by a specific vendor for use with that vendor's product only.

Open protocols are based on industry standards such as TCP/IP or

ISO/OSI models and are openly published.

Modulation: Network modulation refers to the way messages are encoded

for transmission over a cable. The two most common types are broadband and

baseband.

Network transmission interfaces

The vast majority of PLC communications is done via RS232C and

twisted pair cables. Most PLCs have an RS232 port and are capable of

handling communications with host computers, printers, terminals, and other

devices. Maximum transmission speed is Kbps.

The distance and data transmission rates are standards for the various

interfaces. Their actual performance is a function of the driving devices and

varies significantly between manufacturers. As such, you should consult the

manufacturer's specifications for actual distance and data transmission rate

capabilities.

The only real limitation on RS232C is the 50-ft recommended distance

between devices. While RS232C installations often can achieve cabling

distances greater than this, the "unbalanced" design of the interface results in a

greater susceptibility to surrounding electrical noise and reduced data integrity.

This is particularly true where electromagnetic interference (EMI) and

radio-frequency interference (RFI) are known to exist.

When longer transmission distances are needed, RS422 is a better choice.

Unlike the RS232C interface, RS422 is "balanced." Each of its primary signals

consists of two wires that are always at opposite logic levels, with respect to

signal ground. As a result, the interface can achieve longer transmission

distance (4000 ft) and higher data transmission rates (up to 90 Kbps). In

shorter runs (less than 50 ft), data transfer can reach 10 Mbps.

Fiber optic communications are gaining greater acceptance and are being

used in more and more installations. Fiber optic cable is virtually impervious

to harsh environmental conditions and electrical noise. Also, these links can

span extremely long distances and transmit data at very high speeds. For

example, in some LAN systems, these links can transmit at relatively high

speeds and span long distances before requiring a repeater. When repeaters are

used, virtually unlimited distances can be achieved.

可编程操纵器技术讨论与以后进展

随着时期的进展,现今的技术也日趋完善、竞争愈演愈烈;单靠人工的操作已不能知足于目前的制造业前景,也无法保证更高质量的要求和高新技术企业的形象.

人们在生产实践中看到,自动化给人们带来了极大的便利和产品质量上的保证,同时也减轻了人员的劳动强度,减少了人员上的编制.在许多复杂的生产进程中难以实现的目标操纵、整体优化、最正确决策等,熟练的操作工、技术人员或专家、治理者却能够容易判定和操作,能够取得中意的成效.人工智能的研究目标正是利用运算机来实现、模拟这些智能行为,通过人脑与运算机和谐工作,以人机结合的模式,为解决十分复杂的问题寻觅最正确的途径

PLC的语言并非是咱们所想象的汇编语言或C语言来进行编程，而是采纳原有的继电器操纵的梯形图，使得电气工程师在编写程序时很容易就明白得了PLC的语言，而且很多的非电气专业人士也对PLC专门快熟悉并深切。

以上仅仅是PLC的优势之一，这也是人们比较容易明白得的一部份，在很多的设备中，人们已再也不希望看到太多的操纵按钮，它们不但容易损坏而且极易产生人为的失误，小的并非是要紧的失误或许你还能够同意；但过大的乃至是致命的失误是咱们无法容忍的。新的技术老是为了给咱们带来更平安和便利的操作，使得咱们面临的一大堆问题一扫而光，你有了解过HMI吗？那个地址说HMI你全然不清楚它是什么，也没有爱好了解，换一个中文把它说明为触摸屏或人机界面你就明白了，它和PLC的结合给了咱们更大的空间。

当咱们在工作完一个工件时，给PLC一个信号，将PLC的内部计数器加1来计算咱们一天的工作量时，一个简单的计数器能解决问题，固然它们也能够在掉电的情形下维持数据，促使数据不丢失，这也是咱们所期望的。

PLC还具有高级计数器的功能，当咱们在同意一些高速的数据时，那

个地址所说的高速是在在微秒级的数据，比如条码扫描机在不断的扫描数据，数据处置器DSP计算的高速信号等，咱们就要采纳到高级计数器来帮忙咱们进行计数。它在PLC执行程序时一旦发觉高级计数器对应的中断，就会当即放下手上的工作。通过再次编程的梯形图程序说明咱们在执行程序时高级计数器会自动的执行对应的工作，从而将高级计数器的级别升至高一级别。

你或许听过太多的那个词:“死机”，大致的意思是CPU工作量过大，内部资源不足等情形造成程序无法运行。PLC也有类似的情形，在PLC内部有一个看门狗WDT，咱们能够设置WDT一个程序运行的时刻，当程序运行进程中显现程序跳转错误时或程序忙碌时，程序的运行时刻超过WDT的设置时刻，CPU转而WDT复位状态。程序从头开始运行，但对中断可不能进行破坏。

PLC的进展已经从单一的模式进入了通信的网络时期，并同其它的工控网板和I/O卡板轻易的进行共享。组态软件能够将所有的这些硬件连接起来，通过更直观的动画图片来进行操纵，并能够通过互联网在异地进行操纵，像神舟五号的发射确实是采纳这种方法来使飞船升空。

更高层次的进展需要咱们不断的尽力来取得。PLC的显现已经足足阻碍了几代人，咱们也从上一辈的体会中获取了更多的知识和教训，来不断的进展PLC技术，将它推向更高浪潮。

了解可用的PLC网络的最正确选择，其应用将确保有效率和灵活的操纵系统设计。可编程逻辑操纵器（PLC的）能够支持多种通信方式的范围，使之成为一个理想的操纵和工业自动化和操纵应用各类设施数据搜集装置。但是，有一些混乱，因为这么多的可能性存在。为了帮忙排除这种混乱，让咱们的通信名单，可何时他们会是最好的应用。

为了了解PLC的通信多功能性，让咱们第一概念描述的各类制度的用语：

ASCII码：这代表着信息互换。1，当字母“A”是传播，例如，它会自动编码为“65由发送设备”。接收设备转换的“65”回答。因此，不同的设备能够彼此通信既是利用ASCII代码的其他长。

ASCII的模块：那个智能PLC模块是用于连接到PLC的通信也利用

ASCII码作为车辆等设备的能力。

总线拓扑结构：这是一个线性局部区域网络（LAN）的安排。 A条，其中个别节点成为窃听通信电缆要紧在单点和广播消息。这些消息对旅行的连接点从两个方向的巴士，直到它们被消耗在每一个终端的巴士底。

CPU：这代表“中央处置单元”，这其实确实是一台运算机，可编程操纵器，智能设备或其他地址的算术和逻辑运算的执行和指令被解码和执行的一部份。

菊花链：这是对单个设备中的PLC网络，连接描述在那里，每一个设备连接到下一个和通信信号从一个单位传递到下一个顺序的方式。

散布式操纵：这是一个自动化的概念，即一个自动化系统的部份是由单独的操纵器，这是在位于其周围地域的直接操纵（操纵分散操纵系统及遍及出）。

主机电脑：这是一个被用来转移的PLC /运算机网络的数据，或接收从一个PLC数据的运算机。

智能设备：那个术语描述了自己的CPU配备任何设备。

I / O：这代表“输入和输出”，这些模块处置数据到PLC（输入），或从PLC（输出信号）至外部设备。

Kbps：这代表“千比特每秒”，这是一个衡量的电子数据传输速度。

Mbps：这第一个字母。“百万比特每秒”

节点：本术语适用于任何立场或在网络电台之一。每一个节点包括一个装置，能够与网络上的所有其他设备。

议定书：数据的概念是如何安排的编码和传输网络上。

环形拓扑结构：这是一个局域网的安排，其中每一个节点连接到两个其他节点，在一个持续的，封锁的，圆形的途径或致使邮件循环流通，通常在一个方向。有些环拓扑结构有一个特殊的“环回”功能，让它们继续发挥作用，即便主缆斩断。

RS232：这是描述具体的线路连接，电压品级的串行通信IEEE标准，和其他经营通信电子数据参数。另外，还有其他一些遥感的标准。

串行：这是一个电子数据传输打算，信息传输一次一个位。

串行端口：这通信上，它被设置为串行通信设备接入点了。

星型拓扑结构：这是一个局域网的安排方式，节点连接到彼此通过一个中央枢纽，它能够主动或被动。活跃的中心执行诸如路由和保护信息网络的职责。中央枢纽只是一个被动的传递沿线的所有连接到它的节点的信息。

拓扑：这涉及到一个节点的具体安排在彼此的关系网络。

透明：那个术语描述事件或进程的自动成一个系统，不需要特殊的编程或操作员提示兴修。

此刻，咱们正在与这些条款熟悉，让咱们看看它们是如安在现有的描述PLC网络选项。

PLC网络方案

PLC的网络提供一个网络方案，以知足特定的操纵和通信需求的各类你。典型的方案包括远程I / O，同辈对同辈，和主机通信，和局域网。这些网络能够提供靠得住和本钱之间的有效沟通少两个或几个100的PLC，运算机很多，和其他智能设备。

许多PLC的厂商提供的专用网络系统，是并世无双的，可不能与另一作出的PLC。这是因为不同的通信协议，命令序列，错误检查打算，并通过传播媒介每一个制造商利用。

可是，它有可能使不同的PLC的“交谈”彼此;什么是需要的，是为连接（第ASCII码接口），和与软件的大量工作。

远程I / 0系统

一个远程I / O配置，如下图。4A条，已实际投入一些从操纵器和CPU的距离和产出。这种类型的系统，它能够作为一个“主人和奴隶式”的配置描述，使许多遥远的数字和模拟点，由一个单一的PLC操纵。通常情形下，远程I / O的连接到CPU通过双绞线或光纤电缆。

远程I / O配置能够极具本钱效益的操纵，是只有少数的I / O点是在分离领域需要普遍的解决方案。在这种情形下，它并非老是必要的，或与此有关的实际，在每一个站点有一个操纵器。它也不是不切实际的个别硬线交回给远程跋涉的CPU每一个I / O点。例如，远程I / O系统可用于购买设备或设施从远程位置的数据。信息，如周期时刻，计数，持续时刻或事件等那么能够被送回PLC的保护和治理报告。

在远程I / O配置，主操纵器民调苦练的I /目前我的O / O状态。远程I / O系统响应，然后与主PLC的信号，远程I / O来改变输出状态，由在PLC的内存操纵程序决定。这整个周期显现每秒数百次。

对等点对点网络

同行的对等网络，如下图。4B条，增强和谐操纵分散在不捐躯靠得住性的操纵功能。在这种类型的网络，众多的PLC连接到彼此在一个菊花链的方式，和一起的经历表中的每一个内存复制。如此，当任何PLC的数据写入到那个内存区，该信息会自动转移到网络中的所有其他的PLC。然后，他们能够利用他们自己的经营方案此信息。

同侪对同侪网络，每一个网络中的PLC是为自己负责操纵现场，只需要为它自己的责任领域编程。这大大降低了网络方面的编程和调试的复杂性;因为所有通信发生对用户透明，通信编程是减少到简单的读取和写入报表。

在点对点的对等系统，有无主人的PLC。可是，它可能指定作为把握PLC的一组作为一个操纵器类型利用。这可用于PLC的然后同意来自运营商输入端子输入信息，例如，把所有必要的参数到其它PLC和和谐各类活动测序。

主机电脑联系

也可连接的PLC与运算机或其他智能设备。事实上，大多数的PLC从小到超级大的，可直接连接到电脑或下降一个多主机通过RS232C或RS422端口的运算机网络的一部份。这种电脑组合，最大限度的操纵功能的PLC操纵和数据搜集，和运算机，数据处置，文件和操作界面。

在一个PLC /运算机网络，所有通信都是由主机电脑，它是连接在一个菊花链方式对所有的PLC。这台运算机的网络地址单独的PLC和每一个具体的信息要求。该处置的PLC然后发送该信息的存储和进一步分析的运算机。那个周期发生每秒数百次。

主机电脑也能够帮忙编程的PLC;壮大的编程和文档软件方案可供开发。然后程序能够写在接力阶梯逻辑的PLC电脑并下载。如此，你能够创建，修改，调试，并通过运算机终端显示器PLC程序。

除主机，PLC的接口往往必需与其他设备，如大型建筑物的平安和治

理系统操作界面终端。尽管很多智能设备能够通过传统的RS232C通信端口和串行ASCII码的PLC直接，一些没有能力的软件接口与个人的PLC型号。相反，它们通常在固定的传送和接收的数据格式。它的PLC程序员有责任提供必要的软件接口。

最简单的方式来提供这种接口的固定格式的智能设备是利用PLC的一个ASCII /大体模块。那个模块大体上是一个小型运算机插入PLC的巴士。配有RS232端口和大体程序，该模块能够很容易处置与周边设备的ASCII通信，数据搜集功能，编程序列，“数字运算，”报告生成和显示，和其他要求。

访问，协议和调制功能的局域网

通过利用标准的接口和协议，许诺局域网的设备组合（可编程操纵器，个人电脑，电脑主机，操作界面终端等），从许多不同的供给商进行通信与网络上的其他人。

访问：局域网的接入方式可避免在网络上的时刻超过一个消息的发生。有两种常见的访问方式。

碰撞检测是其中的节点“听”到网络和传输只有当网络上有无其他消息。若是两个节点同时传输，碰撞检测和两个节点转发，直到他们的消息通过正常。

令牌传递许诺每一个节点传送只有当它在一个特殊的电子称为令牌信息占有的。令牌传递从节点到节点，使每一个有机遇传送不受干扰。令牌通常有一个时刻限制，以避免绑了很长时刻的道理一个节点。

议定书：网络协议的方式界定和安排的信息在局域网上传输编码。下面是两种常见的类型。

专有的协议是唯一的消息的安排，并由他们与该供给商的产品只能利用特定的供给商开发的编码。

开放的协议是依照行业标准，如TCP / IP协议或ISO / OSI的模型，并公布发表。

调制：调制是指网络邮件的方式传输编码的电缆进行测试。两种最多见的类型是宽带和基带。

网络传输接口

PLC的通信绝大部份都是通过RS232C及双绞线电缆。大多数的PLC有一个RS232端口，并处置与东道国电脑，打印机，终端通信能力，和其他设备。最大传输速度为 Kbps。

距离和数据传输率是各类接口标准。他们的实际表现是传动装置制造商之间的功能和显着转变。因此，你应该征询实际距离和数据传输速度能力的制造商的规格唯一的限制是真正的RS232C 50英尺的距离设备之间的建议。尽管RS232C装置往往能够达到比这更大的布线距离的“不平稳”在更大的灵敏性结果的界面设计，周围的电噪音和降低数据完整性。尤其是如此的地址电磁干扰（EMI）和射频干扰（RFI）是已知的存在。

当传输距离更长，还需要的RS422是一个更好的选择。不同的是RS232C接口，RS422接口，是“平稳”。其要紧方面包括各信号的信号地面两条电线是在相反的逻辑电平始终。因此，该接口能够实现更长的传输距离（4000英尺）和更高的数据（90 Kbps）的传输速度。运行在较短（少于50英尺），数据传输能够达到10 Mbps的。

光纤通信正在博得更多人的同意，并正在愈来愈多的设备利用。光纤电缆是几乎不受恶劣的环境条件和电气噪声。另外，这些链接能够跨越很长的距离和传输数据超级高的速度。例如，在一些局域网系统中，这些链接能够在相对高的传输速度和范围之前，需要一个中继距离长。当中继器的利用，几乎无穷的距离能够达到。