Java platform controls the application in systematic platform to consider in open mode
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source:DDON CNC Machining
Summary: Existing open mode controls systematic platform to do not have uniform development standard, for this, the article studied Java -- a kind of advanced true open architecture, application commands the advantage of systematic platform at opening type, and the open sex that how uses Java platform builds unified and open mode to control systematic platform. In the meantime, be aimed at Java platform blemish of real time pilot, offerred a pilot the means of settlement that translate into of real time task is not real time task. Keyword: Java platform; Open mode controls systematic platform; Real time control classifies date: TP273 document label piles up: A article number: The research that foreword of 1001-2265(2000) 02-0036-031 opens type to control a system only then at 80 time. After American NGC(Next Generation Controller) plans, europe rolled out OSACA, japan undertook the name is the research that OSEC plans, canada also has NRC plan. Open mode controls a system not only accrual is mixed at machine tool manufacturer numerical control supplier, also brought very big flexibility to final user. But, the technology that each plans use still cannot come true truly " open " . In the meantime, above plans mutual independence individually, uniform standard and agreement are not had between them, accordingly, go up to be opened truly to still cannot calculating the user. Java is the platform that develops in the light of network environment and a kind of language, since was rolled out by Sun company 1995, cross a lot of advantage such as platform, security to get applied extensively in computer group with its. How does article discussion use Java platform in system of open mode control, achieve the goal of unified platform. The requirement of system of control of 2 open mode opens type to control a system to include the separate package on a group of logic, mix between package the interface between package and applied platform has good definition, make the component that comes from different supplier works in coordination, move on many platform to finish control to work, offer good interface to system of user and other control. Open mode controls a system to have the following characteristic: (The communication system that 1) each other operates a gender to provide an uniform standard will realize data switch. (2) can transplant the standard API that sexual use platform offers, applied process can move on different platform. (3) retractility but aleatoric additions and deletions each function module. (4) but interchangeability but module of aleatoric crossing-over function. A lot of features of the characteristic Java of platform of 3 Java accord with open mode to control systematic demand. Java platform is shown 1 times like the graph. Graph platform of Java of of construction of platform of 1 Java comprises by two structures: (1)Java kind apply program interface with Java: The visit interface that provides a standard to use a program and a few basic kind the library is visited for using a program and expand. (2)Java fictitious machine (JVM Java Virtual Machine) : It is the core of Java platform, it is the key that realizes Java to cross platform. Covered all service function related to platform, include operation of system of user interface, file and network support to wait. Java serves as a kind of brand-new open platform, its become language and structure to have the following advantage: (Strict and all program presses 1) language strictly object-oriented methodological design, can make mistake otherwise. (2) language acceded simply C ＋ ＋ , but take out burden of combination of syntax of head file, finger and operation, structure, operator and empty base kind. (The language with distributed 3) supports a variety of transmission agreements, be like TCP/IP, HTTP and FTP, additional, still support distributed computation. (4) trends allocates memory, assure to use a program in every respect on the safe side assures its security through two kinds of means: ① prohibits pressing with a finger and ② of memory visit run ongoing travel to Java code lawful sex examination, in order to prevent illegal visit data structure, kind with memory. (5) structure is indifferent because compile implement the byte code with immortal indifferent structure can move at any platform, the soft hardware platform that should support Java system only can run byte code. The platform that Java supports amounts to more than 40 kinds, include OS/2, Sun Soloris, Linux, WinNT, Win95, Win98 and VxWorks to wait a moment. (6) can transplant the size of basic data type of sexual Java is affirmatory, its are whole model with floating-point model it is 32, assure those who use a program to be able to transplant quality. (The multi-line Cheng of Java of 7) multi-line Cheng can be in multiprocessing implement on move, be answered it is weller to can be offerred interactively and real time feature. Express as follows with the product contrast of Microsoft. The comparative watch name of the Java that express and Windows product crosses hardware platform to cross software platform security to be able to transplant sexual Java random is aleatoric well WinNT4X86 PowerPCMIPS AlphaDos Windows3xWin95 is better it is better that general Win95X86Dos Windows3x differs Win98X86Dos Windows3xWin95 to differ Win2000X86 AlphaDos Windows3xWin9x WinNT commonly commonly general by the watch 1 visible, control main demand of the system as open mode, java wins out to prepare really. In controlling a system in real time, it is with numerical control machine tool exemple, interpolation and positional control are real time task, in the numerical control system of high accuracy and high rate, interrupt answer speed to be able to amount to small second class, control of this kind of real time calls good real time, be in namely given must end task processing inside time cycle, will bring about the result that cannot expect otherwise. Because this must obtain the CPU of task of every real time handle time and memory to distribute a case, ability is reasonable in systematic load assign real time task and carry out normally. The character of Java and difference of existence of requirement of real time pilot, body is the following now two respects: (The trends management of 1) memory and C ＋ ＋ are different, java keeps clear of automatically for the user memory. It uses a kind to call rubbish to collect implement (the technology of GC) keeps clear of automatically in memory already unused memory space, bring an issue so: User cannot the executive time of predefine GC algorithm, all line Cheng should be hanged when GC algorithm is carried out. This kind of uncertainty and photograph of real time computation are contradictory, because real time is calculated,need decides the executive time of every task accurately. (The Java program that 2) cannot develop to user of rock-bottom hardware visit ought to be have nothing to do with specific hardware and operating system, once the user visits bottom facility directly, certainly will destroys Java cross platform character. The 4 application in opening type to control systematic platform are in numerical control system, applied process can distribute humanness machine interfacial management, three-dimensional emulate with diagnose wait for the real time such as control of real time program and interpolation operation, position to control a process. Real time control asks to interrupt answer speed to want fast and computational amount is large, need alone CPU to handle commonly, the means that perhaps uses hardware to insert card comes true. With the application of OSACA the system is exemple, the double PC structure that if the graph shows 2 times,used: Graph structure of 2 pairs of PC pursues 2 in, HMC(man-machine is controlled) dispute real time task; Axle control of AC-X, AC-Y, AC-Z() with MC(motion is controlled) it is real time task. Axle control and athletic control include interpolation operation and positional control, put in so come true on a PC alone. Mix in real time namely between two PC blame collect between real time TCP/IP agreement has news report. Actually, interpolation operation includes interpolation preparation and interpolation consideration two parts. Inserting complementary operation to regard real time as the task basically is the processing rate that gets CPU of past of be confined to and memory capacity, as high rate, high-powered CPU and high capacity memory appear, the speed that can solve interpolation operation completely wants the issue of data bulk of sue for peace. Can calculate beforehand the XYZ value of off the rails slash coordinate, store in data table, chase again paragraph send to positional control. Current digital servo controller already can dominate the niche algorithm to be included inside, need not develop positional pilot to apply program module again. Accordingly, the development of numerical control application software can differentiate to be not real time task. Additional, if the platform of system of open mode control of current presence is open between OSACA, NGC and OSEC interior. If support the control of the development on the platform of OSACA architecture,use a program the platform to OSACA is open. But each open mode control still cannot come true between systematic platform open, because their architecture is not same, supports agreement and used data structure mutual between did not make public. Accordingly, the communication between them needs to design gateway to come to those who realize data change. See a picture 3. Graph the architecture that the communication Java between system of control of 3 open mode opens as a kind, not just because of its by world place accepted, more important is it has advanced platform to devise a method, become true open platform. At present open mode controls the problem that systematic platform place faces to be able to use Java platform to solve, if pursue,4 are shown. Use what the function that Java platform provides implements hardware and operating system to have nothing to do quality, realize true open control platform. The development of numerical control software is full translate into blame is controlled in real time, applied process gets the support of platform through visitting JavaAPI, use Java language can transplant quality, by modular the applied process of development is had admirable can transplant quality, over the platform that can move at supporting Java. At present a lot of servo controller manufacturers already rolled out the product that is based on Java platform, have the interface of Java, such, build the applied process on Java platform to be able to visit the data of speed servo directly, can solve real time control and the problem that how unite platform thereby. Graph the application of platform of 4 Java 5 conclusion and the plan that looked into the article to put forward to use Java one kind to open type platform truly. The developer of Java also is joining real time function in Java platform, in order to get used to industrial pilot requirement. As the arrival of network times, the platform that is based on Java not only can call open mode to control platform, and still can use its powerful network function to realize different ground to make, will promote the progress that makes adroitly greatly. CNC Milling