Design Of Multifunction Gas Monitor Based On DSP

The industry modernization causes people's living condition develop rapidly, but it also brings some negative effects, makes the condition of air worse and worse, and that influences the environment humanity lives, so the condition of gas is vital important to the humanity.The problem of gas concentration is becoming increasingly serious day by day. Regardless of exceeding value of virulent, flammable gas concentration in the industry or the security index of public situation gas, all above aroused the national department's high attention. The traditional gas monitor aims at one kind of gas, but along with the development of instrument multifunction, the demand for gas monitor which could monitor many kinds of gas was gradually appear. This thesis has designed a multifunction gas monitor, to monitor and record the virulent gas, the flammable gas and the oxygen concentration in the real-time. The monitor also has the function of alarm.After the comparison and the thorough investigation, I chose three electrochemistry sensors designed by the German city company,and the three kind of output signals respectively is 0-1V, 0-1.5V, 4-20mA, and I took the carbon monoxide, the flammable gas and the oxygen as the object to monitor. The kind of gas to be monitored also could be changed correspondingly according to the user demand.The core of this control system is TMS320LF2407DSP manufactured by TI Company. It reshapes, filters and enlarges the signal of flammable gas, virulent gas, oxygen signal, then executes A/D transform, the A/D transformation uses LF2407 which is 10 bit A/D, the following electric circuit LCD real-time reflection gas concentration change, and provides the friendly operation interface to users, two levels of acousto -optics alarm to the gas. The data transmission was realized by using MAX232 and PC. User could examine and transfer historic record if necessary. The gas monitor has a stable operation because of good monitoring processing.