Li Zhihua 0977*), Male, Henan Wugang, PhD student, research direction is vacuum metallurgy.
Computer 1 time current pressure vacuum furnace vacuum furnace inside the vacuum oven Yu Yu vacuum temperature vacuum pump computer's main functions are parameter settings, data display, trend curve display, data preservation.
The main function of the control cabinet is to convert the control commands of the computer into current control signals and control the output current of the thyristor so as to achieve the purpose of temperature control. At the same time, the temperature, pressure, current, voltage and other signals in the vacuum furnace are sent to the computer in real time. Processing.
The main function of the transformer is to convert the mains voltage to low-voltage, high-current electrical energy to meet the vacuum furnace heating needs.
3 System Description 3.1 Control Software Software is compiled in C language, Windows user interface, friendly human-machine interface. The operation interface is divided into parameter setting, real-time display of parameters, parameter curve, bar graph, process flow chart, history record curve and so on. The screen switching adopts pop-up menu, and the operation is simple and convenient. The control mode adopts fold line control. After entering the screen, parameters such as temperature rising slope parameter, control temperature value and constant temperature time are firstly set. After the completion, press the “system startup†button, the system will automatically control and record data according to the set parameters. Automatic cooling after completion.
The 3.2M degree control temperature control adopts the imported SR93 temperature controller, which has advanced control functions such as fuzzy control and two-degree-of-freedom PID. After receiving the upper computer command, the temperature regulator outputs a 420mA continuous PID signal to the thyristor controller. The thyristor controller then controls the output voltage of the power thyristor to control the output power of the transformer to achieve the purpose of temperature control. At the same time, the temperature controller detects the signal from the thermocouple, detects the temperature change in the vacuum furnace in real time and feeds it back to the upper machine. The upper computer then makes an adjustment command according to the feedback conditions.
In this way, a closed-loop control system is formed, which has the characteristics of precision and reliability. The control precision can reach the earth 3.3 Pressure detection Pressure detection Selection of imported vacuum pressure transmitter as a detection instrument, with the characteristics of precision, small drift, long life. The signal output by the vacuum pressure transmitter is directly transmitted to the upper computer via the input module and the communication controller, and is directly displayed by the metering machine. See.
Vacuum pressure transmitter 3.4 voltage, current detection voltage, current detection principle.
The circle 2 pressure test indicates that the field voltage, current detection, and the armature coil AC voltage and current signals are sent to the transmitter and converted to a 420 mA DC standard signal, which is then sent to the computer for processing, display, and storage via the input mask and communication controller.
3.5 System Protection When the system suddenly stops running during the operation, the water cooling system in the vacuum furnace will stop working, resulting in damage to the heating device and insulation material in the furnace; when the water comes in suddenly, it will easily cause water in the vacuum furnace, causing Explosion, so a system of water stoppage protection was also designed in the system. When the water pressure reaches a certain value, the system is allowed to start. When the water is suddenly stopped during operation, the main power supply is automatically forcibly cut off to protect the system.
See the principle.
4 Experiments and Applications When the on-site debugging system is used, the tested functions include: vacuum level, temperature, primary voltage and current, secondary voltage and current change curve display, recording and printing, automatic control and accuracy of temperature rise process, and lower cooling water pressure System self-diagnosis.
It is the main interface of the system, including on-site flow charts, real-time curve data charts and so on. In actual operation, it can display the curve of 5 important parameters in a vacuum smelting operation. It can be seen that the heating curve is very smooth and the insulation is accurate (±1*C). After the insulation is completed, the system automatically turns off the heating power. When a person turns off a cooling water pipe, the system will automatically power off and alarm by sound.
380V power supply 380V water pressure switch DYKY system protection schematic J,-sw fat set | by bwx geisha la crooked 丨 二-1*å²å² | Tian 5 system main interface diagram Vacuum smelting furnace automatic control system has been In October 2003, successfully applied in the Institute of Vacuum Metallurgy and Materials of Kunming University of Science and Technology, automatic control has become a necessary part of the vacuum smelting equipment. With the successful application of the system in a small vacuum furnace, a large vacuum smelting furnace will also be Realize automatic control quickly.
Dai Yongnian, Yang Bin. Vacuum metallurgy of colored gold materials. Beijing. Metallurgical Industry Press, 2003. Dai Yongnian. Non-ferrous metal vacuum metallurgy. Beijing: Metallurgical Industry Press, 1998. Tungsten-antimony alloys and tungsten-rhenium thermocouples. Beijing: Metallurgical Industry Press, 1992. Wang Changzhen. Metallurgical physical chemistry research methods. Beijing: Metallurgical Industry Press, 1982.
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