【正文】 ith the one who knock on door a dialogue, the telephone of this time rang, you signal hint to connect a telephone, after connecting the telephone through, return overdo e together knock on door to have a conversation, after dialogue plete, you continue again to see your book, this kind of circumstance we are called the interruption to it, it has the authority, also having sex of have the initiative, the PLC had such function .Its characteristics lie in us and may meet the urgently abrupt affairs in the operation process of the equipments, we want to stop to start immediately up of work, the whereabouts manages the more important affair, this kind of circumstance is we usually meet of, PLC while carry out urgent mission, total will keep the current appearance first, for example the address of the procedure, CPU of tired add the machine data etc., be like to stick down which the book that we see is when we open the door the page or simply make a mark, because we treat and would still need to continue immediately after book of see the behind. The CPU always does the affair that should do according to our will, but your mistake of give it an affair, it also would be same to do, this we must notice. The interruption is not only a, sometimes existing jointly with the hour several inside break, break off to have the preferred Class, they will carry out the interruption of the higher Class according to person39。 advocates the CPU work, but the spare CPU output is forbidden, when advocates CPU breaks down, spare CPU automatic investment movement. This cut process is controlled by the redundancy processing unit RPU, the switching time in 1~3 scanning periods, the I/O system39。 If cannot meet this kind of requirements, must achieve with the other equipment public earth, forbids to establish contacts the earth with other equipment. The ground point should approach PLC as far as possible. Sixth, the redundant system and hot backup system in profession in and so on petroleum, chemical industry, metallurgy certain systems, the request control device has the extremely high reliability. If the control system breaks down, will create the production suspension, the raw material massive wastes or the equipment trouble, will create the enormous economic loss to the enterprise. But depends on the enhancement control system hardware39。 If must use the expansion unit, its ground point should accept after checking with the elemental area earth in the same place. In order to suppress adds in the power source and the input end, outport39。s place, to guarantee the control system when the heavy accident occurs still the reliable warning and the protection, should have with the significant breakdown the contacting signal to output through the external circuit, caused the control system to move under the safe condition. Fifth, PLC earth the good earth is guaranteed that the PLC reliable work the important condition, may avoid the heterogametic the voltage surge harm. PLC meets the grounding and machine39。 when the power source restores, if RUN input connection, then operates carries on automatically. Therefore, to establish the essential current limiting protection circuit to some easy overloading39。s control system must establish the exterior electric appliance interlock 外文翻譯（ 原文 ） 7 protection。s service life, therefore, time use inductive load the selective relay working life must be long. (4) The PLC output load possibly has the disturbance, must therefore take the measure to control, if directcurrent output39。s load short circuit, will burn down the print circuit wafer, therefore, application fuse protection output element. (3)Uses when the relay outputs, withstands inductive load39。s ties cable should lie alone, prevents the outside signal the disturbance. (5) The exchange output line and the directcurrent output line do not use the identical root electric cable, the output line to be far away from the high tension line and the power line as far as possible, avoids parallel. Third, I/O end wiring 1. Input wiring (1) inputs the wiring not to surpass 30 meters generally. But if the environment disturbance is small, when the loss of voltage is not big, the input wiring may suitable long. (2)Inputs/the output line not to be able to use the identical root electric cable, the input/output line to be separated. (3)Uses the normally opened contact form to connect the input end as far as possible, causes the establishment the trapezoidal chart to be consistent with the relay schematic diagram, is advantageous for reading. 外文翻譯（ 原文 ） 6 2. Outgoing junction (1) The output wiring divides into the independent output and the public output. In not group, may use the different type and the voltage class output voltage. But can only use the identical type, the identical voltage class power source in the identical group39。 (8) Maintenance must be placed after the template installed in place 外文翻譯（ 原文 ） 5 Second, installment and wiring (1) The power line, the pilot wire as well as the PLC power line and the I/O line should distinguish the wiring, between the insulating transformer and PLC and I/O should use the double rubberized wire connection. (2) PLC should be far away from the strong jamming source like electric welding machine, the high efficiency silicon rectifier unit and the largescale power equipment, cannot install with the highpressured electric appliance in the identical switch cabi. (3) The input and output of PLC are best separate the line, the switch quantity and the simulation quantity must separate the placing. The simulation quantity signal39。 (6) pluggable template, to be more careful, gently, and the goods shipped out of static electricity。 (4) before removing RAM modules, check the battery