【正文】 － mail: .The main functions and features of CNC unit 6. Miscellaneous function7. Compensation function 216。 Tool length pensation, cutter radius pensation , and tool nose radius pensation. 216。 Technical parameters pensation 8. Enhanced graphic display function 9. Self173。diagnosis function 10. Communication function 11. Programming function 《 NC Technology 》 E－ mail: .Functional interface between hardware and software in CNC unit 《 NC Technology 》 E－ mail: .HARDWARE ARCHITECTURE OF CNC UNIT216。CNC unit is the core of CNC system. The hardware prising a CNC unit is made up of microprocessors, electronic memory modules, I/O interfaces, and position control modules, etc. , which is just like an ordinary puter system. 《 NC Technology 》 E－ mail: .Types of CNC Unit vby the architecture of printed circuit boards1. All173。in173。one board architecture 2. multi173。functional modules architecture v by the number of microprocessors1. single microprocessor2. multi173。 microprocessorsv by the manufacturing fashions1. ordinary personal puter architecture2. special purpose architecturev according to their opening degree 1. Close architecture2. PC173。plug173。in173。NC architecture3. NC173。plug173。in173。PC architecture4. software based open architecture of CNC unit《 NC Technology 》 E－ mail: .All173。in173。one board architecture vAll173。in173。one architecture CNC unit prises main board, position control card, PLC card, displayer card, and power supply. Main board is a big printed circuit board。 other functional cards are small size, each is installed in a card rack on the main board. 《 NC Technology 》 E－ mail: .Sketch map of All173。in173。one board architecture《 NC Technology 》 E－ mail: .《 NC Technology 》 E－ mail: .Multi173。functional modules architecturevIn this architecture, CNC unit is divided into several function modules. Its hardware and software are designed with modularization method, that is to say, each function module is made of printed circuit of same size, and the control software of function modules are also designed in modularization. Hence, customers can establish their own CNC units by bining their selected function modules into the card racks of a motherboard. CNC control module, position control card, PLC card, graph display card and munication card are familiar function modules. 《 NC Technology 》 E－ mail: .a holonomic CNC lath system 《 NC Technology 》 E－ mail: .Single microprocessor architecture? There is only one microprocessor, which processes various NC tasks by time173。sharing in a centralized control way.? in this architecture. Some CNC system, though having more than two processors ,can only be called single microprocessor systems, because there is only one micro173。processor on duty of controlling and occupying the system bus, while the others cannot occupy the system bus and cannot access main memory. ? This architecture is simple and can be implemented easily, whereas, for reason of centralized controlling, its performances and abilities are limited by the byte length, data width, address ability, and calculating speed of microprocessor. 《 NC Technology 》 E－ mail: .Multi173。microprocessors architecture216。distributed system216。masterandservant system216。 bus based multi host microprocessor system. 《 NC Technology 》 E－ mail: .Distributed system216。 there is a munication work route between each two microprocessors. Interactions within microprocessors and shared resources are achieved via 173。work munication technology 《 NC Technology 》 E－ mail: . Master173。and173。servant system A processor is called master microprocessor, others are servant microprocessors, and they are all independent systems. Only master microprocessor can control the bus, access the resources attached with the bus, control and monitor servant microprocessors, and coordinate