In recent years, programmable logic controller (PLC) has been widely used in engineering, which has attracted wide attention. Therefore, based on the analysis of the meaning and characteristics of the programmable controller, this paper discusses the application of the device in thermal power engineering, numerical control engineering and traffic control, so as to provide reference for people who pay attention to this topic. Programmable Controller (PLC) is a new type of industrial control device, which has been widely used in industrial engineering.
With this device, the production control of various equipment or machinery can be completed, and the performance of mechanical equipment can be improved. In addition, the device can realize the connection between equipment and network, so it can better meet the needs of equipment management. Therefore, it is necessary to analyze the application of programmable logic controller (PLC) in engineering, so as to better promote the application of the device. In the past, people used relays to control industrial engineering systems. However, with the expansion of industrial production scale and the improvement of industrial production speed, the use of relays has been unable to meet the control needs of Engineering systems. In this stage, the microprocessor-based programmable controller has developed rapidly, and has many functions, such as terminal technology, high-speed technology and PID control. At the same time, due to the high cost performance of the programmable controller and the strong ability of communication networking, its application in engineering has been expanding. The so-called programmable controller, in fact, is a digital operation Electronic system, which contains programmable memory, can realize arithmetic operation, sequence control and logical operation and other operational commands, and can carry out the output of analog signals and digital signals [1]. Therefore, the programmable controller can be applied in various kinds of equipment and systems, and can be combined with engineering control system as a whole. From the point of view of technical characteristics, PLC is a general automatic control device, which is based on microprocessing technology and integrates automatic control technology, computer technology and communication technology. The device has the characteristics of strong function, flexibility, simple programming, small size and easy maintenance, and can work stably in harsh working environment.
Compared with relay control system, programmable controller can use program memory instead of hardware wiring to control industrial system, and can control analog quantity and sequence, so its application prospects are broader. In thermal power control engineering, a lot of system procedures need to be dealt with, such as coal slag cleaning, water treatment and coal transportation processes need to rely on the control of procedures. If we want to control these programs, we need to use PLC. For example, in the process of dust removal in thermal power system, the programmable controller can be used to control the blowing time length of the blower, and to control the starting direction and opening and closing time of the air. At the same time, the strength of ash collector, the switch of ash unloading equipment, the start of heater and various valves need to be controlled by PLC technology. At present, the use of programmable controller can not only control some operation links in thermal power engineering, but also control the whole thermal power system. The widespread use of PLC technology has replaced many physical components in the system, and then improved the stability of the system. At the same time, the use of programmable controllers makes the operation of the system more simple. In the process of operation system, operators only need to close and separate operation to complete the control of the system. Because the programmable controller can provide guidance signal to the system according to the actual operation state of the system, the system can automatically complete the opening action once the system fails.
In addition, because the line of the programmable controller has a fixed common end, there will be no errors in the connection process, and there is no need for special flash power supply. With the help of programmable controller, the number of switches used in the system has been significantly reduced, so there will be more unified display signals, which will bring convenience to the operation of system operators. In real life, programmable controller is widely used in numerical control system. At present, PLC can be used for point control and linear control of the system. Compared with the linear control mode, the point control mode has a wider range of applications, and the hole-making machine tool is the main application equipment. In the process of NC machining, the use of PLC can accurately control the movement of machine tools, and complete the accurate positioning of the moving parts of machine tools. The use of programmable controller for machine tool positioning does not rely on other system operations, so there is no need to suspend the operation of the tool in the positioning process. Therefore, the use of programmable controller for traditional machine tool control can improve the control function of machine tools, and make the machine tool system energy consumption, failure, low efficiency and maintenance difficulties and other defects are improved.
In addition, it can also be used in the control of the auxiliary equipment of the machine tool. On the one hand, the programmable controller can be used to control the cooling and lubrication system of machine tools [3].
The control of cooling and lubrication system of machine tools will directly affect the service life and processing accuracy of machine tools, so real-time control and cycle control of the system are needed to avoid waste of resources. The programmable control system can monitor the running state of the system in real time, and adjust the oil quantity of the lubrication system and the circulating time of the cooling system according to the working state of the machine tool, so as to save energy and reduce consumption of the system. On the other hand, programmable controller can be used to control the lighting system. According to the electrical control requirements of machine tools, it is necessary to make the lighting system run at the same time as the machine tool is opened, and close immediately when the control cabinet is closed.
By using programmable controller, the state of illumination system can be displayed by signal indicator lamp, so that the control of illumination system can be simplified. Therefore, the use of programmable controllers for the transformation of traditional machine tools can make CNC processing obtain many advantages, such as high efficiency, low energy consumption and stable work. In fact, the programmable controller has strong environmental adaptability and rich timer resources, so it can be applied in many fields. At present, the programmable controller has begun to develop in the direction of multi-function, which can meet the needs of various projects. The research and development of PLC traffic light controller is to meet the needs of traffic control. With this controller, the precise control of the “progressive” signal lamp can be completed, and the control of multiple intersections can be completed. With the use of PLC technology, communication and networking can also be realized, thus realizing the unattended control of traffic lights.
The programmable control technology combines the signal lights on a road into a local area network, which can also realize the centralized control of traffic lights, thermostatic element thus reducing the waiting time of vehicles, and then making the vehicles run smoothly. At this stage, many brands of PLC contain real-time clock, which can realize 24-hour unmanned management of signal lights.
In addition, the programmable control technology has more decoding instructions, which can complete the conversion of received data, and use seven segments of display code for data transmission, and then use LED digital tube for data display [4]. The use of programmable control technology in lane control machine can also realize the effective maintenance and management of equipment, thereby improving the reliability and service life of equipment.
In a word, with the development of automatic control technology and computer technology, the function of programmable controller has become more powerful, so that it can be applied in many engineering systems. With the development of various industrial engineering, programmable controller will also get more development opportunities, thus bringing more application value to enterprises. Therefore, the application of programmable controller in engineering design will better adapt to the development needs of the times, and then make the related industries achieve better development.