PLC based System for Measuring Concentration of Oxygen in Mines for Miners Safety with O2 Sensor

The health of the human being is always a primary concern of every industry. The mining industry is a risky business. The objective of this paper is to save miners life by considering one measure safety point, measuring the concentration level of oxygen before entering in mines for work. I have used Programmable Logic Control System for converting raw value (electrical signal) generated by O2 sensor to engineering value, which I will display using Human Machine Interface (HMI) readable by humans. As we are aware that in mines there are lots of gases flow in airstream and sometime chemical reactions occurs which affects composition of mine air, results oxidation reduces the percentage of oxygen. So before we enter in mines everyday for work we will measure the concentration of oxygen level in mine. As we already know that dry air contain 20.9470% of oxygen (21% O2) with 78% nitrogen and 1% other gases. We will program our logic by considering the 20% oxygen is present in our mine's atmosphere. If oxygen level varies below 20% than a alarm will trigger, that alarm will display on HMI and Operator will alert miners before any casualty occur.