Several Honeywell MIDAS® cartridges can be configured to read a number of different gases based on a common chemical family. Actual details for the sensor detection range are included in the sensor cartridge specification sheet and the MIDAS® technical manual. MIDAS® sensor cartridges can be ordered as part of a Kit with the universal MIDAS® transmitter, or as a replacement part. The detectable range is listed. With the exception of O2 (where ambient concentration is typically 20.9%), the sensors will display zero when no gas is present. All Cartridges with the format MIDAS-E-XXX are supplied with a 2 year (24 month) warranty.
| Gas Measured | Ammonia (NH3) |
| Cartridge Part Number | MIDAS-E-NH3 | 2 year extended warranty |
| Sensor Technology | 3 electrode electrochemical cell |
| Measuring Range (ppm) | NH3 | 0 – 100 ppm |
| Minimum Alarm 1 Set Point | 12.5 ppm |
| Repeatability | < ± 5% of measured value |
| Linearity | < ± 2% of measured value |
| Response Time t62.5 | < 10 seconds |
| Sensor Cartridge Life Expectancy | ≥ 24 months under typical application conditions |
| Operating Temperature | 0°C to +40°C (32°F to 104°F) |
| Effect of Temperature | < ± 0.1ppm / °C |
| Zero | < ± 1% of measured value / °C (0°C to 25°C) |
| Sensitivity | < ± 0.2% of measured value / °C (25°C to 40°C) |
| Operating Humidity (continuous) | 15 – 90% rH |
| Effect of Humidity | Zero | TBA |
| Sensitivity | TBA |
| Operating Pressure | 90 – 110kPa |
| Effect of Position | No effect in typical application |
| Long Term Drift | Zero | TBA |
| Sensitivity | < ± 3% of measured value / 6 months |
| Calibration Gas | Ammonia (NH3) |
| Challenge Gas (Bump Test) | Ammonia (NH3) |
| Warm Up Time | < 10 minutes |
| Storage Temperature | +5°C to +25°C (+41°F to +77°F) |
Cross Sensitivities
Each Midas 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 NH3) |
| Arsine | AsH3 | 0.2 | 0.07 |
| Carbon Dioxide | CO2 | 5000 | 0 |
| Carbon Monoxide | CO | 100 | 0 |
| Chlorine | Cl2 | 1 | 0 |
| Ethanol | C2H5OH | 1000 | 0 |
| Hydrogen | H2 | 10000 | 0 |
| Hydrogen Chloride | HCl | 10 | -4 |
| Hydrogen Sulfide | H2S | 20 | 2 |
| Iso Propanol | C3H7OH | 1000 | 0 |
| Methanol | CH3OH | 1000 | 0 |
| Nitrogen Dioxide | NO2 | 10 | -0.5 |
| Phosphine | PH3 | 300 | 0 |
| Sulfur Dioxide | SO2 | 20 | -40 |
Honeywell End of Line Particulate Filter
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