With the rapid development of science and technology, social productivity is also gradually improving, people also put forward higher requirements for machine tool control system, so we should focus on the analysis of the application of programmable controller in machine tool control system.
This paper summarizes the characteristics of the programmable controller and the problems existing in the application of the machine tool control system, and puts forward some pertinent suggestions for improvement. PLC (Programmable Logic Controller) was born in the 20th century. After decades of development, its performance has been greatly improved. At the same time, it has many advantages such as easy maintenance, flexible configuration, strong anti-interference, good reliability and scalability. However, the “contactor-relay” control system is still widely used in some backward areas. Because the working efficiency and accuracy of the “contactor-relay” machine tool control system are relatively low, and the problems of difficult maintenance and frequent accidents occur easily in the process of operation. Their automation degree can not meet the actual production demand at present, and restricts the smooth development of industrial production. Therefore, the machine tool control system should be reformed gradually with the help of programmable controller. Machine tools can generally be divided into modular machine tools, thermostatic element drilling machines, lathes and so on, which usually consist of the following components: variable speed structure: can change the actual speed of the main movement of machine tools; supporting components: support, install other parts and components, but also bear their cutting force and weight, such as pillars and machine tools; executing mechanism: an important driving device to complete rotary or linear motion; feeding mechanism: It can change the feed rate of machine tools. The control circuit and the main circuit together constitute the machine tool control system. The former is used to measure, adjust, control and monitor the main contacts and the actual working status of the parameters in the main circuit. The latter is used to control the task circuit or directly responsible for the power exchange.
The control circuit and main circuit are designed according to the real working process of machine tool parts, and control the speed regulation, braking and starting of each motor in the machine tool. In addition, they can control the illumination and cooling of the machine tool. The weight of the super-small programmable controller is less than 150 g, the bottom size is less than 100 mm, and the actual power consumption is only several watts. The super-small PLC is small and easy to install in machinery, which is conducive to the realization of mechatronics. In addition to the basic logic processing ability, the programmable controller can also be used in various machine tool control occasions. At present, most PLCs are used in the field of numerical control for data calculation. In recent years, programmable controller has been widely used in many fields such as temperature control, CNC and position control. The programmable controller uses large-scale and modern integrated circuit technology, and uses new anti-jamming technology in production process and internal circuit. Its reliability is high. In addition, the PLC has the function of automatically detecting the hardware fault. When the fault is detected, it will give an alarm actively. In the process of using the software, the user can program the peripheral device fault diagnosis program into the software, so that the system can get the self-protection function. Programmable controller (PLC) is an important industrial control equipment for enterprises. It has the advantages of easy interface and easy understanding of programming language by engineers.
Especially, its expression, ladder diagram language and graphic symbols are similar to relay circuit diagrams. Only the switch logic instructions of programmable controller are needed to realize the electrical control of machine tools. Wiring logic replaces the storage logic of PLC, reduces the time of designing and building control system and external wiring of control equipment, facilitates the change of program and later maintenance, and can change the production process quickly. The programmable controller can scan all kinds of data information of the input end and save it in the register.
It can refresh the register and then transit to the execution process. At this time, all kinds of components and registers of the programmable controller will be isolated from each other, while the change of external information will not affect the information data of the register. In the same operation cycle, the information data stored in the register has better stability. Qualitatively, there will be no errors due to the change of external information, which lays a solid foundation for the accurate and efficient operation of programmable controller. After collecting information and data, all programs need to be scanned comprehensively according to the operation principle of the programmable controller, and then enter the execution stage. When a programmable controller executes a command, jump instructions often occur.
At this time, jump conditions need to be analyzed in detail and then judged. The jump address directly determines the process. In the process of executing the program, if the jump instructions contain a lot of output or input information, the programmable controller will automatically collect other data information in the previous stage, and then input the terminal state to storage. When the programmable controller finds the current normal working state of the program, it can execute the logical operation, and then store the operation results in the register.
When the operation is finished, it is necessary to analyze the nature and state of the work comprehensively, and then the operation results will change with the execution of the program. The collected information and data are usually stored in the register through the execution stage of the program, and then stored in the latch in the output or input state to output the above processing results and drive the external load accordingly.
Before reforming the PLC, we should first determine the relevant requirements of the electrical control system and the control requirements between the various controls, then analyze the actual workflow of the machine tool to be reformed comprehensively and systematically, and then list the technical indicators and functional requirements of the machine tool control system accurately. According to the actual requirements of machine tool control system, the I/O points of the programmable controller are estimated in detail.
When purchasing the programmable controller, the margin of 10%-15% should be retained on the basis of the actual points. Because there are many types of programmable controllers, I/O points should be considered as the most basic condition for selection, and then the special functions of programmable controllers, data processing speed and data storage capacity should be fully considered. Finally, the programmable controllers with high price and excellent performance should be selected. In some control systems, the corresponding input/output module should be selected according to the signal requirements and types in the “input/output” loop. On the principle of maximizing the use of the original output and input equipment, the required external equipment such as acoustooptic display unit, solenoid valve, button, contactor and sensor should be defined. The hardware design of the system is based on the selected external equipment and programmable controller to modify the control circuit, and draw the safety diagram, electrical layout diagram and wiring diagram of the machine tool electrical control system. In the process of designing the hardware of the system, the same type of output points and input points should be centralized and distributed continuously so as to facilitate reading and writing the program. In the process of programming, the existing contactor relay circuit control schematic diagram can be transformed into corresponding trapezoidal diagram, and then necessary improvement and modification, that is, the so-called empirical design method, if necessary, the new drawing flow chart can be rebuilt according to the actual control requirements of the machine tool, and the PLC program can be programmed by sequential control design and logic design, so that the programmable logic controller can be programmed. The program of program controller is simple and easy to understand. The program in the input programmable controller should be carefully checked: indoor analog debugging can be carried out to check whether the changes of logic functions, output and input meet the actual needs; after the indoor debugging is correct, in order to ensure the accuracy of the external wiring of the programmable controller, on-site debugging should be carried out many times.
If problems are found, they should be solved immediately, and if the expected objectives cannot be achieved, the software should be adjusted in time. Components or hardware facilities. Short circuit or open circuit will affect the complete transmission of the operation signal in the control equipment. If the programmable controller receives incomplete information, the control system will not be able to accurately analyze and judge these incomplete information, which will lead to the occurrence of errors in the control system. The root cause of short circuit or breakage is line failure, for example, long time use of the circuit without proper maintenance and repair. In addition, mechanical pulling, vibration, loosening or insect damage will affect the circuit patency. When the contactor or electric valve fails, the information instruction sent by the programmable controller to the machine tool control equipment can not be transmitted to the executing Party of the information instruction completely, so the executing Party of the command will not be able to complete the preset behavior according to the requirements. The main causes of the above problems are electromagnetic interference or contactor not tightly connected as required.
With the wide application of programmable controllers in people’s daily work and life, the safety of PLC operation and control, the stability of information feedback and instruction transmission and the continuity of control equipment are becoming more and more important. Therefore, the parts and main bodies of programmable controllers should be regularly maintained and repaired, the parts with serious damage and aging should be replaced in time, and the operation of programmable controllers should be upgraded step by step. The function module and interface of the system can enhance the stability of information transmission and the sensitivity of information feedback in the machine tool control system, so that the programmable controller system can better judge and analyze the machine tool electrical equipment. With the help of PLC control system, the data information is collected, then the information is judged and analyzed, and the results of the above information are fed back in time, then the fault reminder function is played; according to the intelligent analysis, the operator is warned of potential safety hazards; the interaction of the above measures can ensure that the operator can find the potential safety hazards in time, and can find, diagnose, analyze and solve the faults in the first time. By collecting, feeding back and checking all kinds of data and information in the production process, the economic loss and loss of life and property caused by mechanical failure and hidden danger can be avoided. In addition, it is necessary to develop modules to deal with failures and potential safety hazards in the operation interface of the programmable controller system, and to provide a solid foundation for the development of enterprises by compiling systematic and humanized programs.
The plasticity of the electronic chip in the programmable controller equipment is strong, which expands the scope of the use of the programmable controller invisibly. This also enables the programmable controller to have more personalized design in the machine control system, thus laying a good foundation for the production safety and stable development of enterprises. By analyzing the application of programmable controller in machine control system, enterprises should gradually enhance the reliability of signal input in programmable controller system and improve the effectiveness of early warning system, so as to ensure the effective use of programmable controller in machine control system, thereby improving the production efficiency, reliability and safety of daily production of enterprises, and promoting the sustainable development of enterprises.