Because of the danger of gas itself and the great harm to people's production and life, the detection and alarm of gas is a necessary task. Gas alarm refers to the use of gas sensor technology to compare the detected gas gas concentration with the standard value. When the concentration is higher than the certain concentration value, the corresponding sound and light alarm is given to remind the working personnel to perform corresponding processing and organize personnel to evacuate or Venting and exhausting mines to avoid unsafe accidents plays a very important role in the safety of the mining industry. The author designed a low-cost flammable gas alarm design that monitors the concentration of gas in the mine, displays the measurement results, and makes judgments about the current environmental conditions and issues alarm information. At present, with the continuous development of mining technology, the safety of underground operations is more and more secure, but there are still many mining companies with low mechanization, which poses a potential threat to the life safety of on-site mining workers, especially for gas. There are still hidden dangers in the detection and alarm, and there are still many serious accidents caused by gas leaks every year. Gas is formed in the process of coal formation and is stored in large quantities in the coal seam. It is the most harmful gas in coal mines. Gas is a colorless and odorless gas. The main component is methane (CH4) with a density of 0.716kg/m3. The harm to the human body is that the time limit can cause suffocation and death. In underground mining, a certain amount of gases such as CH4, CO and SO2 are often leaked in the well. The latter content is low and the cut is easily soluble in water. It is acidified by water spray treatment during coal mining. However, the first two gases are high in content and hardly contain water, and are flammable and explosive gases. System function design system design The gas alarm of this design consists of six parts: sensor, LCD display, sound and light alarm, control circuit, A/D conversion and power module. The gas sensor used in the sensor part can sense certain gases in the environment and will Information about the type and concentration of the gas is converted into an electrical signal. This electrical signal is a continuously changing analog signal that needs to be converted to discrete digital signals by A/D conversion. The control circuit takes the single chip as the core, can process and judge the collected digital signals, and uses a certain algorithm to calculate the gas composition and concentration to be detected and send it to the LCD display for display. An audible and visual alarm is given when the detected gas concentration exceeds the set alarm threshold. The system can store the detected data and the set threshold parameters and provide its own power supply. The system block diagram is shown in Figure 1. Figure 1 overall functional block diagram According to the portable environment requirements of the product design, the core components of the control circuit adopt AT89LV51 low-voltage single-chip microcomputer, and the sensor adopts MQ5 gas sensor. In order to reduce the occupation of the MCU port and further expand other functions, the A/D conversion part adopts TI's TLC1543. The LCD display adopts dm12232f. The A/D conversion and LCD are connected to the single-chip microcomputer through serial mode. The sound and light alarm circuit uses buzzer and LED to alarm. This design can meet different occasions. Application, test results are stable and reliable, 10-bit TLC1543 A / D conversion chip can meet the accuracy requirements of system measurement. The system circuit is shown in Figure 2. Figure 2 system circuit diagram The system adopts AT89LV51 single-chip microcomputer as the core of the control part. AT89LV51 is a low-voltage, high-performance CMOS 8-bit single-chip microcomputer produced by ATMEL. The chip contains 4Kbytes of re-writable read-only program memory (PEROM) and 128bytes of random access memory (RAM). Compatible with the standard MCS-51 command system, built-in general-purpose 8-bit central processing unit (CPU) and flash memory unit, AT89LV51 can work under 2.7 ~ 6.0V power supply voltage. The core device TLC1543 of the A/D conversion section has three control inputs CS, I/OCLOCK, ADDRESS and a data output DATAOUT following the serial peripheral interface SPI protocol. The 51 series MCU does not have an SPI interface built in, but the SPI protocol can be simulated by software. In terms of hardware, the CS, I/OCLOCK, ADDRESS, DATAOUT, and EOC ports of the TLC1543 are connected to the five I/O ports of the AT89LV51. The alarm module uses a buzzer as an audible alarm device to remind the user that the current gas concentration has exceeded the warning line. The operation should be stopped immediately and the corresponding treatment should be carried out to avoid the danger. It is used in conjunction with a liquid crystal display to effectively remind the work environment around the staff and help the staff to improve their safety. In the circuit of the alarm module, when the level of the P0.7 port is low level, the triode is turned off; when the level of the P0.7 port is high, the triode is turned on, and the buzzer generates an alarm sound. Scouring Pad,Industrial Scouring Pad,Nylon Abrasive Scouring Pad,Scouring Pad For Polishing Foshan Nate Abrasive Science & Technology Co.,Ltd , https://www.nateabrasives.com
