Servo drive and position detection device
Function: after receiving the feed speed and displacement command signals from CNC device, and after certain conversion and amplification by servo drive circuit (such as speed control unit), the machine table movement is driven by servo drive device (such as DC servo motor), and the actual position of actuator is detected by displacement sensor and fed back to CNC device to realize closed-loop drive, The position speed of the feed parts of the machine tool is controlled accurately. Dongguan CNC factory is really good, it is worth paying attention to!!
4. auxiliary function driving circuit
This part realizes the information transmission and transformation of CNC device and machine tool strong current. Its function is to accept CNC signal, and control the operation of main shaft, lubrication, cooling, tool changing and other auxiliary functions through strong current of machine tool. In addition, some state information of the machine tool is transferred to CNC device, such as: tool in place, bench over range, etc. In the high-end CNC system, the control work of this part is accomplished by the "internal type" programmable controller (PC) belonging to CNC device, or by the "general-purpose" programmable controller (PC) independent of CNC device.
5. numerical control system software
The whole process of the software is implemented with the support of hardware. Part or all of the numerical control functions are realized by software.
Figure 4-2 is the schematic diagram of Fujitsu CNC system, which is a CNC system of micro-computer. Through this schematic diagram, the composition principle of CNC system can be further understood.
Microprocessor: M6800, 8-bit microprocessor. ROM storage control program, RAM storage intermediate data and user processing program, with input / output interface connected with machine tool operation panel, paper tape reader, hand pulse generator and machine controller, DC servo motor drive, pulse encoder disk detection displacement to realize position feedback. LSI circuit realizes interpolation operation, and its operation speed is high.

2、 Main characteristics of CNC system
The main features of CNC system are as follows.
1. the system is flexible, variable, easy to change and expand, and has strong universality
This is the most prominent feature of CNC system. Unlike hardware numerical control, once a certain mode and function is formed, it can not be changed arbitrarily, because the connection between hardware is realized by wiring. For CNC system, as long as the structure of software is changed, new functions can be supplemented and developed at any time to meet different requirements.
2. easy to realize multi-function
Dongguan CNC processing plant has abundant command system and can carry out complex calculation, so it is much more convenient to realize multi-function and high complexity control than hardware system. For example, high order curve interpolation, tool radius compensation, multi coordinate linkage control, etc., some CNC systems can also carry out numerical control programming when controlling and processing, which is impossible in hardware system.
3. high system reliability
In the hardware CNC system, the processing program is input by the reader one by one in Dongguan CNC processing factory, but CNC system can input the processing program into memory at a time, which can reduce the input failure. Because the hardware of CNC system is much less than that of NC system, the error rate of system components is also reduced relatively, which makes the system work stably and reliably. As the functions of CNC system are realized by software, as long as the software is perfect, it is impossible to produce software operation errors in the continuous work of the system in the future, so the continuous failure free time of CNC system can reach tens of thousands of hours.
4. convenient maintenance
Because of the strong function of CNC system, the system function is modularized, and software fault diagnosis is adopted to make CNC maintenance convenient. Dongguan CNC factory is really good, it is worth paying attention to!!
5. Communication function of CNC system
With the development of manufacturing technology, CNC system is required to be centralized control, so this function is indispensable. For example, in DNC, FMS, CIMS systems, communication is required between systems.