Digital Toxic Gas Detector
Model: 902
1.0 Application
Model 902 are digital gas detectors for CO-carbon-monoxide and NO2 –nitrogen-dioxide concentration monitoring. They are widely used in large vehicle exhaust environment like in-door parking garages or municipal work facilities, warehouses, etc. to monitor concentrations of CO or NO2.
2.0 Working Principle
3.0 Features
- 3 color LEDs indicate communication status, concentration level and trend/numerical display (optional)
- Automatic calibration reminder
- Sensor “End of Life” warning
- Hardware watchdog for high reliability and fail safe operation
4.0 Specification
- Detectable gases: CO or NO2
- Inputs: Two sensors maximum – one local, one remote (4-20mA input).
- Outputs: Modbus RTU, 4-20mA, relay output (standalone version)
- Wiring: 4 Wire ‐ 2 power + 2 communication
- Connection: RS‐485
- Enclosure: PVC
- Supply Voltage: 16‐42 VDC, 12‐32 VAC
- Dimensions: 4” x 4” x 25”
- Operating temperature: ‐20°C to 50°C (‐4°F to 122°F)
- Warranty: 2 years (sensors excluded)
- Indicators: LCD for gas concentration, LEDs for sensor, transceiver operation and fault
- Coverage area: 7500 sq. ft. (50’ radius)
- Recommended mounting height: 4‐5’F.F.
4.1 Carbon Monoxide Sensor for 902‐CO
- Range: 0‐250ppm
- Sensor type: Electrochemical
- Accuracy: 1ppm
- Response time: Better than 30 Seconds to 90%
- Life expectancy: 6 years
- Operating humidity: 5‐95% RH Non‐Condensing
4.2 Nitrogen Dioxide Sensor for 902‐NO2
- Range: 0‐10ppm
- Sensor type: Electrochemical
- Accuracy: 0.1ppm
- Response time: Better than 25 Seconds to 90%
- Life expectancy: Better than 2 years
- Operating humidity: 5‐95% RH Non‐Condensing