外文翻译模板(6)

two maintain a certain ratio between Is obtained by processing the surface of the blade in this movement in the envelope. Gear machining hobbling, gear shaping, shaving, honing, and grinding teeth (not including form grinding teeth), etc. are generating method processing.

PLC

Early called the programmable logic controller PLC (Programmable Logic Controller, PLC), which is mainly used to replace the logic control relays. With the technology, which uses micro-computer technology, industrial control device function has been greatly exceeded the scope of logic control, therefore, such a device today called programmable logic controller, referred to as the PC. However, in order to avoid personal computer (Personal Computer) in the short confusion, it will be referred to as programmable logic controller PLC, plc since 1966, the U.S. Digital Equipment Corporation (DEC) developed there, the current United States, Japan, Germany, PLC Good quality and powerful.

The basic structure of Programmable Logic Controller

A. Power

PLC's power in the whole system plays a very important role. If you do not have a good, reliable power system is not working, so the PLC manufacturers design and manufacture of power very seriously. General AC voltage fluctuations of +10% (+15%) range, you can not take other measures to PLC to connect directly to the AC line.

B.Central processing unit (CPU)

Central processing unit (CPU) is the central PLC control. It is given by the function of PLC system program from the programmer receives and stores the user program and data type; check the power supply, memory, I / O and timer alert status, and to diagnose syntax errors in the user program. When the PLC into run-time, first it scans the scene to receive the status of various input devices and data, respectively, into I / O image area, and then one by one from the user program reads the user program memory, after a shell and press Provisions of the Directive the result of logic or arithmetic operations into the I / O image area or data register. And the entire user program is finished, and finally I / O image area of the state or the output of the output register data to the appropriate output device, and so on to run until stopped.

To further improve the reliability of PLC, PLC is also large in recent years constitutes a redundant dual-CPU system, or by three voting systems CPU. Thus, even if a CPU fails, the whole system can still work properly.

C.Memory

Storage system software of memory called system program memory. Storage application software of memory called the user program memory.

D.Input and output interface circuit

1, the live input interface circuit by the optical coupling circuit and the computer input interface circuit, the role of PLC and field control of an interface for input channels.

2, Field output interface circuit by the output data registers, interrupt request strobe circuit and integrated circuit, the role of PLC output interface circuit through the on-site

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