Paper on Electrical Control and plc Technology 1 Research on Electrical Control and PLC Technology
Driven by today's high-tech level, all technical equipment is constantly upgrading, and the requirements for electrical control systems are getting higher and higher. In the practical work of the electrical industry, the addition of PLC technology has greatly promoted its development, improved the quality of electrical control while improving the electrical system, which has a great impact on the future development of the electrical industry.
Technical analysis of electric control PLC
From the appearance, PLC has the characteristics of small size and light weight. Generally, the size of the bottom of a small PLC does not exceed 100mm and the mass does not exceed 150g, which is convenient for installation and assembly with the electrical system. PLC has a wide range of applications, which can be used in general electrical control places, especially digital control. In addition, the application of anti-interference technology provides a strong guarantee for the safety and reliability of the electrical control system. The setting of PLC external detection system provides good conditions for fault detection inside and outside the system. Moreover, the installation and operation of PLC are simple and easy to understand, and people engaged in electrical control are also easy to master. Storage logic is used by PLC technology in practical application, which is simple in wiring, convenient for future maintenance and transformation, reducing workload and improving work efficiency.
Workflow after integration of 1 PLC technology and electrical control
Electrical control mainly ensures the normal operation of electrical equipment by controlling primary and secondary circuits, which has become an indispensable role in modern industrial automation and an important weapon to promote the development of industrial automation. The essence of PLC technology is a kind of controller, which is specially used for professional control. It is a communication controller mainly developed by computer, communication technology, automation and other technologies. The integration of PLC technology and electrical control technology can produce strong anti-interference ability and self-diagnosis ability, improve the electrical control system and effectively eliminate the faults in the system.
At present, PLC technology is widely used in electrical control industry, and many enterprises begin to pay attention to the introduction of these foreign technologies. As an important role in modern electrical control industry, the application of PLC technology will greatly promote the development of electrical control industry. At the same time, if we want to combine PLC technology with electrical control reasonably, we must have a certain grasp and understanding of PLC technology, which is the premise and important foundation for better application of PLC technology in practice. In addition, PLC technology is also widely used in industrial systems, such as petroleum, building materials, steel, chemicals, electricity, machinery manufacturing, automobiles, transportation and so on.
Combined with the work flow of PLC, according to the actual work experience, the work flow after the integration of PLC technology and electrical control is divided into three stages. It mainly includes collecting and inputting original data, executing user programs and refreshing output.
(1) Collecting data is the first step in the working process of PLC. Read and store the input status points and data in turn by scanning, and store them in the corresponding units in the I/O image area. After completion, enter the refresh stage of user program execution and output. At this stage, the state and data of the corresponding unit in the I/O image area will not change.
(2) On the basis of completing the first step, scan the user program from top to bottom. The user program is the execution phase. In the concrete implementation, the control circuit on the left side of the user program is scanned first, and at the same time, the logical operation of the control circuit composed of contacts is still executed in the order from top to bottom and from left to right. Similarly, the status and data of cells in the I/O image area will not change, but the status and data of other output points and soft devices in the I/O image area or system RAM storage area may change.
(3) 3) The last stage of PLC workflow, namely the output refresh stage. After the user program scanning is completed, PLC will enter the output refresh stage. At this stage, the CPU refreshes all output latch circuits according to the state and data of the corresponding I/O image area, and then the output circuits complete the driving settings of the corresponding devices, which is the final output process of PLC.
The work flow of PLC is similar to most other mechanical equipment, and it is a cyclic process. These three working stages are cyclical, and every three stages are a cycle. The integration of PLC technology and electrical control technology not only improves work efficiency, but also saves the cost of fault and development and research.
2 PLC technology in the application of electrical control common problems
System control failure. It is possible that the control fails due to the aging of the line and the destruction of the surrounding environment, so that the signal cannot be transmitted to the inside of the system, the data cannot be received, loaded and converted, and other execution commands issued by the system cannot be received.
Data acquisition and transmission failures may also be caused by improper operation of switches and other equipment, such as incomplete opening and closing, inability to receive or receive error information, which leads to control operation errors and abnormal system operation, that is, PLC cannot receive signals and the control system fails.
The failure of equipment switch and field transmitter is also the reason why PLC technology can't work normally. The failure may be due to poor connection and damage, and the above PLC control and analysis system can't receive data and further process it. In addition, human error is also one of the causes of system failure.
3 PLC technical problems corresponding solutions
Attach importance to the reliability of signals input into PLC control system. Ensure that the performance of all field equipment and related components is in good condition, and avoid the phenomenon that signals cannot be sent and received normally due to equipment parts problems. In addition, updating and perfecting the main interface function module settings is also conducive to reducing control errors.
Improve the system settings to make it more reliable, automatic and integrated. When the PLC electrical control system is damaged or wrong, it plays an alarm role in the early warning system. This function is very important in the control of PLC system, which can effectively monitor the working situation and reduce the losses caused by instruction errors to the system. Ensure the operating environment around PLC, eliminate interference factors in time and implement 24-hour monitoring.
Strengthen the technical training of personnel, improve their professional ability and self-cultivation, encourage employees to learn new technologies, methods and skills, and improve the quality of work.
4 abstract
In the face of the rapid development of high technology, in order to develop healthily and long-term in any field, we must constantly learn and master new technologies. Only by fully understanding and learning new technologies and equipment and applying them reasonably can we really gain something. PLC plays a huge role in electrical control, and the integration of the two will greatly promote the progress and development of the electrical control industry.
refer to
[1] Niu Yun. Research on Key Technologies of Main Processor in Computer Control and Management System of Advanced Aircraft Electrical System [D]. Northwestern Polytechnical University, 2006.
Chen Shi. Research on Single Electrical Control Technology of MW Wind Power Generation System ―― Reactive Power Compensation and Yaw Control System [D]. Nanjing University of Aeronautics and Astronautics, 2004.
Zhou Shiqiang, Guo Qiang, Zhu Tao, Liu Xudong. Analysis and Research on Electrical Control and PLC Application Technology [J]. China Dwellings (next issue), 2014,01:199.
[4] Fu Huansen, Li Yuangui. Research on project-driven teaching based on the training of engineering applied talents ―― Taking the course of electrical control and PLC technology as an example [J]. Popular science and technology, 20 12.
Brief introduction of the author
Zhang Che (198 1-), male, from Zhangjiagang, Jiangsu. Bachelor degree. Intermediate engineer. The research direction is electrical automation control.
Author unit
Zhangjiagang Shagang Group Zhangjiagang City, Jiangsu Province 2 15600
Electrical Control and plc Technology Paper 2 Application of Electrical Control and PLC Technology
Aiming at the weakness of traditional CNC lathe in automatic control function, taking CK6 140 common CNC lathe as the object, the electrical control of CNC lathe is discussed in detail, the automatic transformation function of CNC lathe based on PLC is realized, and the detailed electrification and automation transformation scheme and control structure are given, which has good reference significance for further improving the application of PLC automatic control technology in electrical control field.
Keywords: electrical control; PLC technology; Automation; unattended
1 Introduction
With the gradual development of programmable controller (PLC) technology, many industrial productions require the realization of automatic control functions, and all of them use PLC to build automatic control systems. Especially for some electrical equipment and large electromechanical equipment with complicated electrical control, PLC has unique advantages in electrification and automatic control, such as sequential control, high reliability, good stability, easy networking and remote control construction, and unattended implementation. Based on this, PLC technology has gradually become the main application technology of industrial electrical automation control.
This paper mainly discusses the application of PLC technology in the electrification transformation of CNC machine tools, and the application of PLC technology in realizing the automatic control function of CNC machine tools, and shares it with colleagues.
2 Overview of electrification transformation of CNC machine tools
2. 1 Main functions of CNC machine tools
CNC machine tools are the most widely used electromechanical equipment in machining, manufacturing and production. CNC machine tools rely on CNC programs to realize automatic cutting and machining of parts. However, at present, there are still 10 million CNC machine tools in China, which mainly rely on manual control to complete cutting, and cannot achieve basic electrification and automatic control. Therefore, the main purpose of this paper is to realize the electrification transformation of CNC machine tools based on PLC control technology, and mainly realize the following functions:
(1) All motors and contactors of CNC machine tools are automatically controlled based on PLC;
(2) The feeding movement of the CNC machine tool is automatically completed by PLC control without manual intervention;
(3) Automatically detect the relevant parameters in the cutting process of parts, such as machining parameters and state parameters;
(4) The remote control of CNC machine tools can be realized by combining with the upper computer, so as to achieve the purpose of unattended operation.
2.2 Overall plan for electrification transformation
Combined with the above functional requirements for electrification and automation transformation of CNC lathe, the automation transformation scheme combining upper computer and lower computer is determined. The overall structure of the scheme is analyzed as follows:
(1) With the help of industrial computer and its powerful image processing ability, the upper computer mainly completes the display of production configuration screen of CNC lathe, as well as the transmission, storage and output of necessary production data. At the same time, it can also issue relevant control instructions to ensure that the CNC lathe can automatically complete all cutting production tasks.
(2) The lower computer adopts the electric control mode based on PLC technology, and the sensor and data acquisition board are responsible for collecting all parameters of the CNC lathe, such as production data, environmental data and status data. , the relevant data is calculated by PLC and transmitted to the upper computer for graphic display and storage; On the other hand, the PLC control system also receives the control instructions from the upper computer to realize the remote control of the CNC lathe.
(3) For the most critical control of CNC lathe, the mode of PLC+ motion control card is adopted to realize electrification and automation control. The specific implementation method is: select the appropriate motion control card and cooperate with the sequential control of PLC to realize the servo motion control of the feed shaft motor, so as to realize the automatic control of the feed motion of the CNC lathe.
Realization of automatic control transformation of NC lathe electrification
3. 1 structural design of system transformation
The overall structure of electrification automatic control transformation of CNC lathe is shown in the following figure 1, which mainly consists of the following parts:
3. 1. 1 bottom equipment
The underlying equipment mainly includes two aspects. First, the electrical and mechanical equipment necessary to realize the basic functions of CNC lathe, such as power module and motor module, can ensure the stable and reliable realization of the basic functions of CNC lathe. Secondly, the bottom equipment also includes various sensors, such as speed sensor and temperature sensor for monitoring motor speed and temperature, grating ruler for monitoring feed speed of feed shaft, etc. These sensors and data acquisition devices provide basic data sources for the automatic control of CNC lathes.
3. 1.2 local PLC station
The local PLC station is mainly responsible for receiving sensing parameters, state parameters and other detection parameters from the bottom sensing equipment, judging the working state of the whole CNC lathe through the operation of internal programs, and uploading key parameters to the remote control terminal for graphic display, storage, output printing and other operations of data; On the other hand, the local PLC station also receives the control instructions of the remote control terminal, such as stop and start, and the PLC station controls the corresponding actuator (such as motor) to realize the function of automatic control.
3. 1.3 remote control terminal
The remote control terminal mainly relies on the industrial computer to realize the data management and state monitoring of the upper computer. Therefore, it is necessary to develop a set of software programs for the processing, production and automatic control of the CNC lathe to realize the remote, networked and automatic control of the CNC lathe and truly realize the unattended function.
3.2 Design and Implementation of PLC Electrical Control System
This research paper takes CK6 140 common machine tool as the specific research object, and discusses its electrification and automatic control transformation in detail. Through the above analysis of the machine tool transformation scheme and structural function, it can be determined that the electrification and automation transformation of the whole machine tool needs 14 system inputs and 9 system outputs. According to the control requirements, FX2N-48MR PLC of Mitsubishi Corporation of Japan is selected here, and the input loop is powered by 24V DC power supply. According to the analysis of the control function of each module of CNC machine tools, appropriate electrical control elements such as contactors, relays, switches and auxiliary contacts are selected to control electrical equipment together with PLC. For example, PLC controls the motor module through contactor and the solenoid valve through relay, thus completing the electrification transformation of CNC lathe based on PLC control.
4 conclusion
With the increasing complexity of electrical equipment, the requirements for electrical control in industrial production are getting higher and higher. The automatic control technology based on PLC has been widely used and has gradually become one of the mainstream technologies of industrial automatic production control. The biggest advantage of adopting PLC technology is that it can realize automatic control, high reliability and strong anti-interference ability, which greatly avoids the system instability caused by adopting single chip microcomputer technology. In this paper, the application of PLC automation technology is discussed in detail in combination with electrical control, and a specific system design example is given, which has good guidance and reference significance for further improving the industrial application of PLC automation technology.
References: