Because of its convenience and reliability, PLC programmable logic controller technology has been effectively used in mine electromechanical control, greatly improving the efficiency of mining. PLC programmable logic controller is a kind of embedded microcomputers widely used in modern industrial control. It can easily replace the old relay control system.
Compared with traditional relays, PLC programmable logic controller technology has better reliability and stability, and wider application space. PLC technology is simple to operate, with ladder diagram as the main programming mode, and its daily management and maintenance are relatively simple, which satisfies the general technical requirements of industrial production in China. The advantages of PLC control system are easy disassembly, small size and flexible adaptability to various sites.
Through the connection of programmable logic controller and output device, it is very convenient to control electromechanical equipment. The working principle of PLC: PLC is composed of input and output interface, power supply, programmer, expansion interface, memory, device interface and central processing unit.
Data exchange between PLC mainly depends on the three middle bus of power supply, address and data to connect, control the corresponding equipment according to need, and execute its operation. The application of PLC technology is usually accomplished through its superior performance, and has its own unique advantages. Its combination is very flexible, its function is perfect, and its practicability is strong.
At present, the functions of PLC technology are very powerful. Each module and unit can be combined freely, which can meet the requirements of many systems. From this, it can be seen that it is very suitable for industrial control needs [1].
The working procedure of the programmable logic controller has the following processes: (1) running state detection. In the operation of the equipment, the PLC scans the running state of the electromechanical equipment, completes the checking of the running state data, and stores the state data in the corresponding memory.
In the specific operation, it is necessary to strictly ensure the safety factor of the switch status of the connecting points in the mine electromechanical control system. In a word, the PLC system should first be based on the detection of the running state, and run through reliable programs to effectively improve the efficiency and reliability of the control system. (2) Procedure running process. After the data acquisition is completed, the state data is processed by standard, thermostatic element and the complete input is judged and calculated in the processor. The calculated output data is saved to the corresponding processor unit. Finally, all the state data in the electromechanical control system are output to the output of the PLC, and then the electromechanical equipment is controlled by the current output signal. At present, the effective way to reform mining machinery is to upgrade it with PLC technology. Through the output of the PLC system, a high-power controller and a high-power thyristor are connected to realize the current transformation of the hoist, so as to improve the reliability and operation efficiency of the hoist. In practice, the mechanical operation and DC motor parts of the mechanical and electrical system can be kept unchanged when PCL technology is applied to the upgrading of the elevator. From the overall analysis of the electromechanical control system, it is the most feasible method to transform the original relay in electromechanical equipment by using programmable controller and high-power AC. The problem that needs to be clarified and noticed is that in the process of upgrading and transformation, we usually take the method of retaining the old console. On the one hand, it is necessary to remove the old operating platform and create favorable conditions for the installation of the new one. On the other hand, when using the new console control system, the old and new control systems can coexist and backup each other. The main purpose is to further improve the reliability of the system as a backup under very special circumstances. When engineers and technicians transform the old mine hoist, they should first design a thorough upgrade plan, then give more reasonable suggestions for improvement through expert argumentation, and then select engineers and technicians who have been strictly trained to install and debug, laying a solid foundation for improving the quality through a series of measures and guarantee mechanisms. In the technical transformation of mine hoist PLC, debugging is the most important and tedious step. In debugging, we must pay attention to the lubrication degree of each mechanical connecting part and the travel state of braking system, and record strictly. The position data of the mechanical switch are detected by corresponding electronic control, and the state data are also recorded strictly. Before the transformation, the mechanical fault must be eliminated completely, so as to avoid the problem of operation failure in the process of operation of the machinery after the transformation. Finally, we must also pay attention to the strict joint control of the old and new systems in the process of PLC technical transformation of mine hoist. The reason is that the joint control of the old and new systems can not only effectively realize the control of loading and unloading and lifting signals, but also reduce the difficulty of debugging the old and new systems. When the PLC control system in the operation process, in the effective use of PLC technology, we must first make a simple analysis of the data. In the calculation of motor speed, in order to reduce the impact of mechanical operation and improve the frequency of motor operation, the use of power units to deal with renewable energy is an indispensable link. The process information recorded by the PLC control system can be stored in the internal memory of the system. In order to ensure the validity of the monitoring data of the PLC control system, the refresh time period is generally set to 1 second. The switch data are recorded by the processor, and then the data information is calculated to get the speed of the winch. On the other hand, the direction of winch operation should be controlled.
When the winch start button is pressed, the winch is always in a horizontal state of operation. Two monitors are used to record the switch effectively. If the state data changes within five minutes after the start, only another counter is needed to control, and the rising contactor will produce a strong attraction pull. When the drawing winch runs, the winch rises. Every 5 seconds is a winch operation cycle period, within which each contactor will return to the starting state during the process of rising and falling.
When the winch is in the state of over-speed operation, the system gives a warning. In the process of winch speed control, if the speed exceeds a certain limit, the PLC control system will automatically issue corresponding instructions, which are displayed by the display, and the driver can see the corresponding data.
The control unit of PLC requires high temperature, which must be kept in the temperature range of 0 50. When the ambient temperature of the PLC control system is too high, the failure of the PLC system will seriously threaten the reliability and service life of the PLC system.
If the temperature is too low, the circuit drift phenomenon of the PLC system will be serious, and the operation of the system will become very slow, affecting the safety performance of the equipment. When the temperature is below 0 C, the drifting phenomenon of the PLC system circuit will be more serious, and the system may collapse.
Therefore, in our daily work, we will place the PLC control system in the appropriate temperature in order to maximize the advantages of the PLC control system. With the increasing level of coal mine automation, PLC programmable logic controller technology occupies an indispensable position in the field of automation control, and has been widely used in mine mechanical and electrical equipment control. From the development of coal industry, the main mode of PLC programming based on trapezoidal diagram is simple to operate, simple to design, easy to master by engineers and technicians, and simple to maintain and manage daily equipment, which greatly meets the technical requirements of industrial production in China. All in all, the application of PLC technology in mine mechanical and electrical control has a great prospect.