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Dual Sensor

Dual Sensor
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Dual Sensor Carbon Monoxide Hydrogen Sulfide Miniature Size PATENTED and PATENT PENDING Introduction The world wide use of multigas, portable, personal safety monitors has grown since the 1970s to include an ever increasing number of industries. The one requirement in common to the majority of these instruments is the need to measure both Carbon Monoxide and Hydrogen Sulfide simultaneously. Alphasense now offers a compact, dual gas sensor which allows designers to reduce significantly instrument size and cost. The D2 sensor provides a unique approach to the dual gas sensor in both its size and working electrode configuration. The use of a high capacity filter over the Carbon Monoxide working electrode eliminates Hydrogen Sulfide cross sensitivity to Carbon Monoxide. Proven in the field over many years, these sensors perform well even under long term, challenging conditions. D2 Specification Carbon Monoxide Channel PERFORMANCE Sensitivity nA/ppm in 400ppm CO 27 to 55 Response time t90 (s) from zero to 400ppm CO < 25 Zero current ppm equivalent in zero air < ± 6 Resolution rms noise (ppm equivalent) 1 Range ppm CO limit of performance warranty 1000 Linearity ppm error at full scale, linear at zero and 400 ppm CO < 40 Overgas limit maximum CO for stable response to gas pulse 5000 LIFETIME Zero drift ppm equivalent change/year in lab air < 0.5 Sensitivity drift % change/year in lab air, monthly test < 4 Operating life months until 80% original signal (24 month warranted) 24 Zero @ -20oC ppm equivalent change from 20oC -1 to 1 Zero @ 50oC ppm equivalent change from 20oC -1 to 4 CROSS Filter Capacity ppm-hours of Hydrogen Sulfide 15,000 SENSITIVITY H2S sensitivity % measured gas @ 20ppm H2S < 8 NO sensitivity % measured gas @ 50ppm NO < 50 SPECIFICATIONS Pressure range kPa 80 to 120 Humidity range %rh continuous (see note below) 15 to 90 Storage period months @ 3 to 20oC (stored in sealed pot) 6 Load resistor Q (recommended) 10 to 47 Note: Above 85% rh and 40OC a maximum continuous exposure period of 10 days is warranted. Where such exposure occurs the sensor will recover normal electrolyte volumes, when allowed to rest at lower %rh and temperature levels for several days. NOTE: all sensors are tested at ambient environmental conditions, with 10 ohm load resistor, unless otherwise stated. As applications of use are outside our control, the information provided is given without legal responsibility. Customers should test under their own conditions, to ensure that the sensors are suitable for their own requirements. At the end of the product’s life, do not dispose of any electronic sensor, component or instrument in the domestic waste, but contact the instrument manufacturer, Alphasense or its distributor for disposal instructions. Alphasense Ltd, Sensor Technology House, 300 Avenue West, Skyline 120, Great Notley. CM77 7AA. UK Telephone: +44 (0) 1376 556 700 Fax: +44 (0) 1376 335 899 E-mail: sensors@alphasense.com Website: www.alphasense.com

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erformance Data Performance Data Carbon Monoxide Channel Figure 2 CO Channel Sensitivity Temperature Dependence 130 Figure 2 shows the variation in sensitivity caused by changes in temperature. The data is taken from a typical batch of sensors. Figure 3 CO Channel Zero Temperature Dependence Zero output, referenced to 20oC (equivalent ppm) Figure 3 shows the variation in zero output caused by changes in temperature, expressed as ppm gas equivalent referenced to the zero at 20OC. This data is taken from a typical batch of sensors. Figure 4 CO Channel Response to High CO Concentration 300000...

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Performance Specification continuedD2 Specification Hydrogen Sulfide Channel PERFORMANCE Sensitivity nA/ppm in 20ppm H2S 90 to 160 Response time t90 (s) from zero to 20ppm H2S @ 20oC < 30 Zero current ppm equivalent in zero air < ± 1 Resolution rms noise (ppm equivalent) <0.25 Range ppm H2S limit of performance warranty 100 Linearity ppm error at full scale, linear at zero and 20ppm H2S 0 to -9 Overgas limit maximum ppm H2S for stable response to gas pulse 400 LIFETIME Zero drift ppm equivalent change/year in lab air < 0.1...

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erformance Data Performance Data Hydrogen Sulfide Channel Figure 5 H2S Channel Sensitivity Temperature Dependence Figure 5 shows the variation in sensitivity caused by changes in temperature. The data is taken from a typical batch of sensors. Zero output, referenced to 20oC (equivalent ppm) Figure 6 H2S Channel Zero Temperature Dependence 1.0 Figure 6 shows the variation in zero output caused by changes in temperature, expressed as ppm gas equivalent referenced to 20oC. This data is taken from a typical batch of sensors. Figure 7 Ambient Long Term Test Results 160 Figure 7 shows good long...

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