The Midas-M Sensor Cartridge enables the detection of a wide range of asphyxiant, toxic, flammable, pyrophoric, corrosive, and oxidizer gases. The plug & play Sensor Cartridge is located inside the detector’s chassis.
Note: The O3 sensor CANNOT be combined with an SO2 sensor in a complete Midas-M Sensor Cartridge Package.
| Gas Measured | Ozone (O3) |
| Cartridge Part Number | MMS-U2 |
| Sensor Technology | 3 electrode electrochemical cell |
| Measuring Range | O3 | 0 ppm to 0.4 ppm |
| Default Alarm 1 | 0.05 ppm (rising) |
| Default Alarm 2 | 0.1 ppm (rising) |
| Accuracy | <±10% of measured value |
| Exposure to O3 0.2 ppm for 5 minutes |
| Response Time (t62.5) | Typical 13 seconds |
| Sensor Cartridge Life Expectancy | 24 months under typical application conditions |
| Operating Temperature | 0ºC to 40ºC (32ºF to 104ºF) |
| Effect of Temperature | Zero | <±0.0018 ppm/ºC |
| Sensitivity | <±0.8% of measured value/ºC |
| Operating Humidity (continuous) | 20% RH to 75% RH |
| Effect of Humidity | Zero | Abrupt changes will cause a short term drift |
| Sensitivity | <±1% of measured value/% RH |
| Operating Pressure | 70 kPa to 110 kPa |
| Effect of Position | No effect in typical application |
| Long Term Drift | Zero | No drift |
| Sensitivity | <5% of measured value/6 months |
| Calibration Gas | Ozone (0.1 ppm to 0.3 ppm, default 0.2 ppm) |
| Challenge Gas (Bump Test) | Nitrogen Dioxide (1 ppm) |
| Warm Up Time | < 10 minutes |
| Storage Temperature | 5°C to 25°C (41°F to 77°F) |
Cross Sensitivities
Each Midas-M sensor is potentially cross sensitive to other gases and this may cause a gas reading when exposed to other gases than those originally designated. The table below presents typical readings that will be observed when a new sensor cartridge is exposed to the cross sensitive gas (or a mixture of gases containing the cross sensitive species).
| Gas / Vapor | Chemical Formula | Concentration applied (ppm) | Reading (ppm O3) |
| Ammonia | NH3 | 100 | -3 |
| Arsine | AsH3 | 0.2 | 0 |
| Carbon Dioxide | CO2 | 5000 | 0 |
| Carbon Monoxide | CO | 100 | 0 |
| Chlorine | Cl2 | 1 | 1.2 |
| Chlorine Dioxide | ClO2 | 1 | 1.5 |
| Chlorine Trifluoride | ClF3 | 1 | 1 (Theoretical) |
| Fluorine | F2 | 0.1 | 0.1 |
| Hydrazine | N2H4 | 3 | -3 |
| Hydrogen | H2 | 500 | -0.05 |
| Hydrogen Chloride | HCl | 4 | 0.4 (Overrange) |
| Hydrogen Fluoride | HF | 6 | 0.4 (Overrange) |
| Hydrogen Sulfide | H2S | 20 | 1.6 |
| Nitric Oxide | NO | 100 | 1 |
| Nitrogen | N2 | 100% | 0 |
| Nitrogen Dioxide | NO2 | 10 | 6 |
| Sulfur Dioxide | SO2 | 4 | 0.4 (Overrange) |
AC Power supply assembly for M2/M2A, input 100 VACC to 240 VAC, output 24 VDC, mounted in 18-0400RK
1 × $204.75 
