【正文】 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 hardware 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 blastoff 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, ing to the continuous development PLC technique, push it toward higher wave tide.Booming automobile industry to the automotive parts industry has brought unprecedented opportunities for development . Induction heating technology in the field of automobile manufacturing is also being more widely used.In melting , the metal casting is an easy method for forming processing . The method can be made by casting the various automotive parts of plex shapes and sizes . Things can be said in terms of development of automobile industry the best use of almost all of the casting process for the automotive industry can do everything . Domestic and foreign auto parts casting melting process of production are used mainly cupola melting process, the intermediate frequency induction furnace melting process and cupola double frequency induction furnace melting process , and induction melting furna。s request. This kind of breaks off the medium interruption to also became to break off the set. The Class that certainly break off is relevant according to various resources of CPU with internal PLC, also following a heap of capacity size of also relevant fasten.The contents that break off has a lot of kinds, for example the exterior break off, correspondence in of send out and accept the interruption and settle and the clock that count break off, still 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。 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 Internet 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 data signal and the clock signals to be carry on by the CPU to send out at the same time, this needs to all want the specialized clock signal each other to carry on the transmission and connect to send, and is constrained, the characteristics of this kind of method lies in its speed very quick, but correspond work time of take up the CPU and also want to be long oppositely, at the same time the technique difficulty also very big. Its request lies in ting have an error margins in a data deliver, otherwise the whole piece according to pare the occurrence mistake, this on the hardware is a bigger difficulty. Applied more and more extensive in some appropriative equipments, be like the appropriative medical treatment equipments, the numerical signal equipments...etc., in pare the one data deliver, its result is very good.And the different step is an application the most extensive, this receive benefit in it of technique difficulty is opposite and want to be small, at the same time not need to prepare the specialized clock signal, its characteristics to lie in, its data is partition, the longlost send out and accept, be the CPU is too busy of time can grind to a stop sex to work, also reduced the difficulty on the hardware, the data throw to lose at the same time opposite want to be little, we can pass the examination of the data to observe whether the data that we send out has the mistake or not, be like strange accidentally the method, tired addition and eight efficacies method etc., can use to helps whether the data that we examine to send out have or not the mistake occurrence, pass the feedback to carry on the discriminator.A line of transmission of the information contains a string of and bine the cent of: The usual PLC is 8 machines, certainly also having 16 machines. We can be at the time of sending out the data a send out to the other party, also can be 88 send out the data to the other party, an and 8 differentiations are also that we say to send out the data and bine sends out the data. A speed is more and slowly, but as long as 2 or three lines can solve problem, and can use the telephone line to carry on the long range control. But bine the oscular transmission speed is very quick of, it is a string of oscular of 25600%, occupy the advantage in the short distance, the in view of the fact TTL electricity is even, being limited by the scope of one meter generally, it bine unwell used for the data transmission of the long pull, thus the cost is too expensive.Under a lot of circumstances we are total to like to adopt the string to bine the conversion chip to carry on deliver, under this kind of circumstance not need us to carry on depositing the machine to establish too and plicatedly, but carry on the data exchanges through the data transmission instruction directly, but is not a very viable way in the correspondence, because the PLC of the ot