SO2-B4 Sulfur Dioxide Sensor 4-Electrode PERFORMANCE Sensitivity nA/ppm at 2ppm SO2 275 to 475 Response time t90 (s) from zero to 2ppm SO2 < 30 Zero current nA in zero air at 20â?? -80 to +80 Noise* ±2 standard deviations (ppb equivalent) 5 Range ppm limit of performance warranty 100 Linearity ppb error at 100ppm SO2 , linear at zero and 10ppm SO2 0 to -2 Overgas limit maximum ppm for stable response to gas pulse 200 * Tested with Alphasense ISB low noise circuit LIFETIME Zero drift ppb equivalent change/year in lab air < ±20 Sensitivity drift % change/year in lab air, monthly test < ±15 Operating life months until 50% original signal (24 month warranted) > 36 ENVIRONMENTAL Sensitivity @ -20â?? (% output @ -20â??/output @ 20â??) @ 2ppm SO2 70 to 82 Sensitivity @ 50â?? (% output @ 50â??/output @ 20â??) @ 2ppm SO2 95 to 110 Zero @ -20â?? nA change from 20â?? 0 to -10 Zero @ 50â?? nA change from 20â?? 10 to 30 CROSS SENSITIVITY Filter capacity ppm·hrs 450 H2S sensitivity % measured gas @ 5ppm H2S < 2 NO2 sensitivity % measured gas @ 5ppm NO2 < -160 Cl2 sensitivity % measured gas @ 5ppm Cl2 < -40 NO sensitivity % measured gas @ 5ppm NO < -2 CO sensitivity % measured gas @ 5ppm CO < 2 H2 sensitivity % measured gas @ 100ppm H2 < 0.5 C2H4 sensitivity % measured gas @ 100ppm C2H4 < 1 NH3 sensitivity % measured gas @ 20ppm NH3 < 0.1 CO2 sensitivity % measured gas @ 5% CO2 < 0.1 KEY SPECIFICATIONS Temperature range â?? -30 to 50 Pressure range kPa 80 to 120 Humidity range % rh continuous (see note below) 15 to 90 Storage period months @ 3 to 20°C (stored in sealed pot) 6 Load Resistor ohm (ISB circuit is recommended) 33 to 100 Weight g < 13