Application of AI-719P intelligent industrial regulator in silicon molybdenum rod heating furnace
Yudian temperature controller, Xiamen Yudian Automation Technology Co., Ltd. Silicon molybdenum rod is widely used in metallurgy, steelmaking, glass, ceramics, refractory materials, crystals, electronic components, semiconductor materials research, manufacturing and other fields, especially for Production of high-performance precision ceramics, high-grade artificial crystals, precision structural cermets, glass fibers, optical fibers and advanced alloy steels. If it is matched with the intelligent temperature control system, it can obtain accurate constant temperature, and can control the temperature adjustment according to the actual needs of the production process. The good and accurate control of the temperature control automation control system of the silicon molybdenum rod heating furnace will play an important role in the production of the product, so it is very important to choose an accurate and stable temperature controller. The price of imported instruments is expensive, and the cost performance of domestic instruments is relatively high. In many domestic instruments, we are more optimistic about Xiamen Yudian's AI7 series products, so we choose AI-719P as the core of the control system. Smart Light,Smart Strip Light,Smart Ceiling Light,Smart Breaker JIANGMEN MOSCOT OPTOELECTRONIC TECHNOLOGY CO.,LTD. , https://www.jmsensorsled.com
First, the basic principles of the system
For a high-temperature furnace whose load is non-linear, its resistance will change drastically with temperature. Taking a silicon-molybdenum rod furnace as an example, its room temperature is about 6% when the resistance is only 1600 degrees, if the output power of the meter is not limited. And transformation, will lead to two problems, first of all, the electric furnace current is too large when starting at low temperature, exceeding the maximum allowable load of the grid, thyristor and transformer, causing damage to the thyristor, electric furnace, transformer or causing the grid to trip, in addition, because the meter is the same When outputting, the power of the electric furnace in the low temperature zone and the high temperature zone will be more than 10 times, which means that the proportional band P in the PID parameter needs more than 10 times change at different temperatures, so that the low temperature and high temperature zones can be accurately realized. Temperature control, and the method of limiting the parameter OPH can only limit the output power, and the proportional band conversion cannot be realized. If the high and low temperature areas can meet the precise temperature control, it is necessary to set multiple sets of PIDs, which is not only complicated but also has poor effects. .
The custom output limit conversion function of the Yudian AI-719P meter also solves the function of limiting the output and transforming the proportional band P. This function limits and changes the output of the meter according to the measured temperature, which not only limits the power in the low temperature zone but also Automatically correct the proportional band parameters at different temperatures, and the power limit and the proportional band change are continuous fold lines, which is better than the grouping method. The power limit only reduces the actual output of the meter proportionally and the meter output display range is still It is 0~100%.
Second, the system control program
The heating unit used in the scheme is a U-shaped silicon molybdenum rod. The control method is single-phase 380VAC on the transformer side and 80V on the secondary side. The control uses the two-way thyristor phase shift trigger to control the conduction angle of the thyristor. The instrument selects Yudian AI- The 719P precision artificial intelligence industrial regulator and the Yudian AIJK-1J single phase phase shifting trigger are matched as the core control equipment. AI-719P series thermostat is a precise and stable, powerful, environmentally friendly and energy-saving artificial intelligent temperature controller. It also has a custom output limit conversion function suitable for silicon molybdenum rod heating furnace control. Compared with other types of instruments on the market, it can be more Precise and stable temperature control. The silicon molybdenum rod has an electric power of about 28 kW, a primary side of 380 VAC, and a secondary side of 80 VAC. Combined with a primary voltage and current, the power of the scheme is 30 KW, and the primary side and secondary side voltages are respectively 380 /80.
Third, the instrument settings
The internal parameter OPT of the instrument is set to 4-20, and the input type INP is set to the sensor type, wherein the P, I, and D parameters are written by the instrument self-tuning, the trigger is set to 4-20ma signal control, and other common parameters can be maintained at the factory value. The custom output limit conversion can be set as follows: A00=1, A 01=1050, A 02=100.0; A03=1200; A04=100.0, d 00=600.0; d01=800, d02=1000, d03=1000, D04=1000, d05=1200, d06=1200, d07=1400, d08=1400, d09=1400, d10=1600, d11=1600, d12=2000. When the parameter A 00=1 and A 01=1050 are set, the instrument enables the custom output limit conversion function, A 02 represents the starting temperature of the output limit, A 03 represents the highest temperature of the output limit, and A 04 represents the nonlinear data temperature. The length of the segment is 1200/100.0=12 in this example, indicating that there are 12 segments. The more segments, the more complicated the curve can be. d 00 represents the maximum output power below A 02, the unit is 100% × (A02 / 2000), d 00 = 600.0 means 30%, d 01 means 40%, d 02 means 50%, and so on. The meaning of this curve is that the output limit is 30% when the temperature is below 100 °C, the power limit is smooth from 30% to 40% between 100 and 200 °C, and the power limit is 40% between 200 and 300 °C. Transition to 50%, and so on, the temperature above 1300 °C is not limited to 100%.
Fourth, summary
In the control system of the silicon molybdenum rod heating furnace, the domestic instrument should say that it can fully meet the control requirements of the whole system. From the perspective of cost performance, the domestic watch should far exceed the import table. Xiamen Yudian's AI-719P is a good domestic instrument that we use at present. The control accuracy and stability are better.
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