Application of PID Controller AI-808
Abstract: This paper describes the application of Yudian PID Controller AI-808 in the high-temperature alumina manufacturing process of a chemical workshop in China Aluminum. It also introduce the production process, structure and process control of the system. The control system is fully standardized, modularized and systematically designed with flexible and convenient configuration, which greatly improves the reliability of the system and reduces the production cost of the equipment.
Key words: PID controller AI-808 , batching system, process control, proportional adjustment
The ultrafine aluminum hydroxide series products such as low iron, low silicon and high white crystal are directly separated from the production process. The particle size is between 0.8 and 1.0 μm with the form of uniform, single crystal. The drying process of ultra-fine materials is a very important in the production of ultra-fine products. The drying process directly determines the quality, price and market of the product. This requires a certain proportional relationship between the drying temperature and the amount of material. In addition to the normal control system, the Yudian PID Controller AI-808 plays a decisive role in this system.
2. System process and structure
2.1 System process
The ultrafine aluminum hydroxide and boric acid are mixed by the upper line through the speed regulating belt scale and the quantitative feeder according to the formula, sent to the high temperature rotary kiln for sintering through the screw feeder, and then cooled by the cooling cylinder to generate high temperature oxidation. Aluminum is finally packaged into finished products through quantitative packaging scales.
2.2 System structure
The system mainly mixes two kinds of materials (such as boric acid and aluminum hydroxide), mainly from raw material workshop main belt, quantitative feeder (speed belt scale), boric acid quantitative feeder, screw feeder, high temperature rotation Kiln, cooling cylinder, finished packaging scale and an industrial control microcomputer and configuration software. Among them, the quantitative feeder (embedded electronic belt scale) is mainly composed of instrument control cabinet (embedded computer integrated calculator and AI-808 intelligent regulator, etc.) and inverter cabinet.
3. The working principle of the control system
When the system is running, the unloading control mainly measures the material conveyed by the electronic batching belt scale. The weighing instrument and the speed signal are received by the control instrument, and after processing, it is converted into the accumulated value and the instantaneous flow rate, and the accumulated value and the instantaneous flow rate are obtained. The signal is transmitted from the RS-485 port to the industrial control unit (host computer), and is transmitted to the Yudian PID controller AI-808 with a 4~20mA analog current signal. The PID controller compares the signal with the set value sent by the DCS. After that, the 4~20mA analog signal is sent to the inverter, and then the inverter adjusts the speed of the conveyor. When the flow rate increases, the speed of the conveyor is reduced, and vice versa, so that the flow rate of the conveyed material is increased. And the cumulative amount of the phase is kept within the set range, and thus the reliable product quality is obtained.
3. System configuration plan and its implementation
3. 1 Upper unit
The upper computer adopts Advantech IPC-610 industrial computer and adopts SIEMENS configuration software, 256 points. It can communicate with weighing control instrument and AI-808 intelligent controller: read data, send data; and communicate with PLC: read I/O status, send I/O command; have alarm, fault inquiry and Print function; the configuration screen truly reflects the real-time status; the engineering settings and recipe input are diverse, and the ability to adapt to working conditions is strong; the software has different access rights, allowing different rights to manipulate different content.
3. 2 Lower unit
(1) Weighing control instrument
The weighing control instrument is the core component of the electronic belt scale. It accepts the weight signal and speed signal from the scale body, and calculates the instantaneous flow rate and cumulative amount. It can display the heavy load, instantaneous flow rate, belt speed, tare weight and alarm signal. content. The instantaneous flow signal is transmitted to the AI-808 PID controller via a 4-20 mA linear analog output.
(2) Yudian AI-808 artificial intelligence PID Controller
The system uses the Yudian PID controller AI-808 (V7.0 version), which is compared with the V6.5 version of the controller, using a new terminal arrangement, a newly designed panel with 10 LED indicating display; added heating/cooling dual output function, the second output can be freely defined as current or time proportional output specification; the alarm adopts one-sided hysteresis; supports up to 4 alarm and event output operations; the sampling rate is increased by 1 time. Enables faster valve control.
The AI-708 controller also features a manual/automatic bumpless switching operation with manual auto-tuning and display output values, as well as a proportional output for servo amplifiers that directly control valve position. AI artificial intelligence regulator can display measured values and set values, with advanced AI artificial intelligence adjustment algorithm, no overshoot, self-tuning AT function and automatic / manual two-way undisturbed switching and user parameter programming functions; 4～20mA linear analog input and output, RS-485 serial communication interface and relay alarm output interface. Compared with the general PID regulator, it adopts fuzzy rules for PID adjustment, which can improve the response speed while reducing overshoot. The general PID algorithm can accurately control the adjusted object, but has the disadvantages of large overshoot, difficult PID identification, and slow recovery of disturbance. The fuzzy adjustment algorithm can adapt to large lag objects, the overshoot is small, and the parameters are easy to determine, but the control effect is relatively poor, and the control curve will produce tiny zigzag fluctuations.
On one hand, the adjustment algorithm of AI artificial intelligence controller improves the PID algorithm, such as adding differential integral function in PID adjustment; On the other hand, it adopts fuzzy adjustment rules. When the error is large, the fuzzy algorithm is used to adjust to completely eliminate PID saturation integral phenomenon. When the error is small, the improved PID algorithm is used for adjustment, which has the characteristics of no overshoot, high precision control, and simple parameter determination.
The artificial intelligence adjustment algorithm has a learning function that automatically learns system characteristics. When the auto-tuning is completed, even if the initial control is ineffective, very precise control can be obtained in the second use.
In the system, the 4~20mA instantaneous flow signal sent by the computer totalizer is received by the PID Controller AI-808, and compared with the target value set by itself, a signal of 4-20 mA is sent to the frequency converter, and the frequency is controlled by the frequency converter. The tray feeder is used to achieve the predetermined ratio, and thus the importance of the PID Controller AI-808 in the system can be seen. The specific model of the PID Controller AI-808 in this system is AI-808-A-I4-X-L1-L1-S4-N. The specific settings are shown in Table 1:
Table 1 AI-808 parameter list
HIAL 70 P 30 Sc 0 bAud 9600 EP4
LoAL -0.5 t 12 OPt 4 dL 3 EP5
dHAL 99.99 Ct1 5 oPL 0 run 1 EP6
dLAL 99.99 Sn 15 oPH 100 Loc 1 EP7
dF 3 diP 2 ALP 5503 EP1 EP8
CtrL 3 diL 0 CF 8 EP2
M5 20 diH 20 Addr 1-2 EP3
(3) Programmable controller
Select S7-300 PLC produced by SIEMENS, power supply 307-1KA01-0AAC, CPU315-2AG10-0AB0, network adapter card CP343-1, digital input module 321-1BH02-0AA0, digital output module 322 -1BH01-0AB0 four blocks, analog module SSM331-TKF02-0AB0 eight blocks. The programming software is WINCC configuration software and so on.
The inverter uses FRN3.7G11S-4CX manufactured by Fuji.
The system was put into use in November 2007. Through the use of the user's site for more than half a year, the system has good reliability, simple operation, convenient maintenance, high system precision, not only guarantees the quality and output of the product, but also guarantees the quality and output of the product. Overcoming the problem of environmental pollution, creating good economic benefits for the enterprise, the stability and reliability of the system and the stability and reliability of the AI-808 PID controller are inseparable. It is another classic case of the application of the AI-808 in non-ferrous metals.