Gas Control System for Tunnel Kiln Kiln production of actual needs, but also changed the original production process backward, inefficient production status of two major technical indicators and system composition gas imprison lI; Bei Liao track kiln kiln control structure diagram of control structure is shown in Figure l. Bury given system the main technical indicators are as follows: 1. 48 of the gas tunnel kiln for accurate sample temperature measurement points, the precision of not less than 5 ‰,ugg boots, showing the point temperature at any time, record each class of data. 2. Production process data can be saved each class can be preset high and low temperature alarm. l996-0l i received a 12-strong wine cream Professor Zhai Yu Ren. What counted in fan applications in teaching and research work, dry. 79 Zhai J Lin Yu-gas Measurement and Control System by kiln shake 3. Under the condition of the equipment in good condition, activation of Microcomputer automatic control section of the furnace temperature activation maximum error ± 5 ℃, the system continuously. Orbital ring Figure 2 Control System for the above target, a hierarchical distributed control system design. Superior machine with PC/AT286 for management. With data logging, temperature display, time print, abnormal temperature alarm. Mcs 51 with a lower machine microcontroller subsystem. Complete data acquisition, control calculation, the output control signals and other functions. On the lower line of communication between the use of silk, the system block diagram shown in Figure 2. 3 System hardware design 3.1 MCU MCU subsystem block diagram of the subsystem design, see Field 2. SCM system to Mcs @ 081 as elimination of a heart, program memory and data memory respectively EPROM2764, RAM6116. Parallel I / O port 8255 for data collection, I/oEl8155 for output control. Assigned by the unified address decoder 74LS138, 1488,1489 composed of non-standard RS - 232 serial port. Microcontroller in the system receiving the higher level machine control parameters sent command and control, automatic sampling and real-time control operations. 3.2 Data acquisition system data acquisition system is composed of multiple switching, amplification, S / H, A / D converter circuit. Multi-channel switching circuit consists of 14 analog switches CD4051 and 2 decoder 74LS138 component,tory burch outlet, which can complete the thermocouple signal to switch the positive and negative whip, and avoid the negative total of thermocouple signals to the adverse effects arising. Analog switches and decoder A. A. A signal output from the MCU subsystem 8255C mouth, in coordination with the software, you can order in complete independence of the input signal 56 to switch. Ao-type computer systems of small magnification, S / H. A / D converter circuit use U.S. BB data produced by high-precision measurement module SDM857. This cross-block contains the following independent circuits: high-precision amplifier. S / H circuit, high-speed high-precision 12-bit A / D converter and clock control circuits. A / D conversion speed 25vs, linearity error of 0.064, the amplifier gain and the clock circuit can be easily adjusted. 3.3 Output Control System gas tunnel kiln is the pneumatic membrane actuator valve, using industry-standard signal 4 ~ 20mA, DC signal is converted to standard atmospheric pressure 0.2 ~ lkg / cm. The output of the circuit including the control system, 14 Way D / A converter 0832. Each output of 0832 with the current transformation are, adders and depth of the negative feedback current output circuit. Therefore has a strong load capacity,tiffany deutschland, the output ~ ~ 20mADC signal control valve of the trip. In order to ensure the fire is not out the mouth. Lower limit of the output signal sent to 4.2mA. 4 4.1 control system software design model,ugg boots sale, then q total gas tunnel kiln in the regular fluctuations in pipeline pressure, itself has a special structure. Which has distinctive features. (1) fire-breathing mouth more, up and down before and after impact each other, l4; (2) by indirect heating furnace wall behind a large I (3) by the climate, the pressure effect is very obvious; round the only single-loop control can not get to meet the requirements the effect, so the system used in cascade PID control mode. The structure shown in Figure 3. Figure Schematic diagram of the main circuit ID control deviation: eI (n) = Ri (n) - yl (nJ its main circuit: R (n) - the main circuit setting Y-(n) - the main circuit is control parameter (T) n - The number n of a sample 1 - the last sample number of incremental output PID formula △ R. △ R2 (n); KPi [eI (n) a eI (n-1 )] + K 【】 eI (n) + KDl [△ eI (n) ~ △ el (n-1)] the main circuit of the output R: (n) {R2 (n) a R2 (n A 1) + △ R2 (n) R (n) - Deputy Vice-back loop across settings deviation e (n); e2 (n) a R2 (n) A Y2 (n) Y: (n) - Vice-loop is Control Parameters