【正文】 ll have the WDT to reset the interruption etc., they enriched the CPU to respond to the category while handle various business. Speak thus perhaps you can39。s automatically coded as 65 by the sending equipment. The receiving equipment translates the 65 back to the letter A. Thus, different devices can municate 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 municating using ASCII code as a vehicle. Bus topology: This is a linear local area work (LAN) arrangement, as shown in Fig. 2A, in which individual nodes are tapped into a main munications 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 puter, 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 work, where, as shown in Fig. 3, each device is connected to the next and munications 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 puter: This is a puter that39。 because all munications occur transparently to the user, munications programming is reduced to simple readandwrite statements. In a peertopeer system, there39。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 mon types. Proprietary protocols are unique message arrangements and coding developed by a specific vendor for use with that vendor39。t have the software ability to interface with individual PLC models. Instead, they typically send and receive data in fixed formats. It39。 what39。s) ability to support a range of munication 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, let39。t send out and accept at the same time, for example when you make a phone call is to can39。 But lead even is a fatal error greatly is what we can39。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 personnel39。s labor strength, reduce the establishment on the personnel. The target control of the hard realization in many plicated production lines, whole and excellent turn, the best decision etc., welltrained 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 person39。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 manmachine interface you knew, and it bines with the PLC to our larger space. HMI the control not only is reduced the control press button, increase the vivid of the control, more main of it is can sequence of, and at can the change data input to output the feedback with data, control in the temperature curve of imitate but also can keep the manifestation of view to e out. And can write the function help procedure through a plait to provide the help of various what lies in one39。t answer the phone, the other party also。s list what munications are available and when they would be best applied. To understand the PLC39。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 masterandslave 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 costeffective control solutions where only a few I/O points are needed in widely separated areas. In this situation, it39。s the PLC programmer39。s access method prevents the occurrence of more than one message on the work at a time. There are two mon access methods. Collision detection is where the nodes listen to the work and transmit only if there are no other messages on the work. 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 it39。s memory. This entire cycle occurs hundreds of times per second. Peertopeer works Peertopeer works, as shown in Fig. 4B, enh