【正文】 t prehend the internal structure and operation orders of the interruption pletely also, we do a very small example to explain. Each equipments always will not fet a button, it also is at we meet the urgent circumstance use of, that is nasty to stop the button. When we meet the Human body trouble and surprised circumstances we as long as press it, the machine stops alloperations immediately, and wait for processing the over surprised empress recover the operation stop the internal I/ O of the internal CPU of the button conjunction PLC to connect up, be to press button an exterior to trigger signal for CPU, the CPU carries on to the I/ O to examine again, being to confirm to have the exterior to trigger the signal, CPU protection the spot breaks off procedure counts the machine turn the homologous exterior I/ O automatically in the procedure to go to also, be exterior interruption procedure processing plete, the procedure counts the machine to return the main procedure to continue to 1:00 can what to explain is we generally would nasty stop the button of exterior break off to rise to the tallest Class, thus guarantee the safety. When we are work a work piece, giving the PLC a signal, counting PLC inner part the machine add 1 to pute 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 datas 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 highspeed 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 can39。t do other works. When you are reading the book, you hear someone knock on door, you stop tostart up of affair, open the door and bine to continue with 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 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。 But whole pair works is both can send out and accept the data, and can send out and accept at the same time. Be like the Inter is a typical example. The process that information transport also has synchronous and different step cent: The data line and the clock lines are synchronous when synchronous meaning lie in sending out the data, is also the d