In CNC machining, for complex parts machining, such as turbine blades, the NC program based on tiny straight segments generated by CAD/CAM can reach several megabytes. For these NC programs with very large programs, they are called huge NC programs.

For the CNC system with dedicated architecture, the NC program has limited storage space. When interpreting a huge amount of NC programs, the RS-232 communication interface is generally used. It is inconvenient to process complex parts while processing, and it also increases the cost of the CNC machining system. , reducing the reliability of CNC machining. For the CNC system based on the industrial PC platform, there is only 640k of basic memory. Since the operating system and the CNC system control software occupy a certain amount of memory space, when it is necessary to explain the operation of a huge amount of NC programs, the huge NC program is generally divided into multiple blocks. The system allocates memory according to the size of each program. If the allocation is unreasonable, it needs to be re-blocked, which brings inconvenience to the operation. The Huazhong I type CNC system uses the industrial PC as the platform. For the processing of huge programs, it realizes the interpretation of huge NC programs by using the extended memory of the system, and at the same time is compatible with NC programs written in high-level language BASIC. Configure the system's extended memory based on the user's maximum processing needs. The system uses extended memory, makes full use of the PC's software resources, uses the extended memory device management program EMM386.EXE, uses DOS 67H interrupt to read and write the physical page of the high-end memory, and completes the logical page operation of the extended memory [1]. Before the CNC system runs, it needs to be loaded in the CONFIG.SYS file:

DEVICE=C:\HIMEM.SYS

DEVICE=C:\EMM386.EXE

1 NC program before loading <br> <br> NC program load detection program detects how much extended memory, how to run the NC program, depending on the required NC program determines whether the processing load.

Whether it is a manual NC program or a huge number of NC programs, the runtime uses unified extended memory for loading. In order to use the system's extended memory, you need to call the multiple sub-functions of the DOS 67H interrupt. First apply a handle containing a certain number of logical pages, and then clear these extended memory, empty and then transfer the NC program into the extended memory, so that the size of the NC program to be processed has nothing to do with the basic memory of the system, only with the system's extended memory. related. The NC program can be loaded and put into operation as long as the extended memory of the CNC system is satisfied. The NC program first loads the physical page of the high-end memory, and then loads the NC program into the extended memory logical page through the mapping relationship between the physical page and the logical page. After the program starts running, you can select the program you want to edit based on the remaining memory of the prompt.

After massive 2 NC program interpretation program into extended memory <br> <br> logical pages, explaining the operation of the program is high in physical memory pages, then put the contents of the extended logical page paged memory mapped to The physical page of the high-end memory, and then explain the NC program in the physical page. To operate on the physical page of the high-end memory, it is necessary to constantly consider the conversion of the logical page involved in the transformation of the program pointer and whether the number of logical pages of the program pointer exceeds the total number of logical pages owned by the handle [2]. This requires that the logical position in the logical page on the extended memory corresponding to the program pointer is recorded when the program pointer is changed, which is called the program logic pointer. The actual physical location of the program pointer in the high-end memory physical page is called the actual pointer of the program. The program logic pointer moves from the logical low address to the logical high address in the extended memory, and the actual pointer of the program is only moved back and forth in the physical page until all the program lines have been interpreted. The program logic pointer has a corresponding relationship with the actual pointer of the program, and a structure is designed to replace the program pointer of the program interpreter based on the system S basic memory, and is used to record the logical position of the program.

Struct Page ProgPtr{

charhugeProgPtr;.∥The actual pointer of the program in the physical page int NumOfCurPage; ∥ the current logical page int PagenumOfHandle; ∥ the number of logical pages owned by the handle unsigned int Handle; ∥ current program handle}

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Aluminum Roller Shutter Door

Material characteristic: Using high quality aluminum extruded shutter profiles, multi-layer painting or film layer surface have excellent scratch resistance function, not decay, wearable and anti-collision.Nice white profiles, accepting mass customization according to users requirements(light gray, brown, cream, wood, fused, sand color and light sand color ,etc.)