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Basic Function:

The 3500/63 Hazardous Gas Monitor is a six-channel monitor that provides different levels of alarms based on the concentration of flammable gases as part of a safety system.When the monitor sounds an alarm, it indicates that the gas concentration is sufficient to pose a threat to personal safety due to explosion or asphyxiation.

• Applicable Sensors and Measurement Methods: The monitor is designed for use with heated catalytic bead gas sensors (such as hydrogen and methane sensors) to indicate the concentration of hazardous gases as a percentage of the lower explosion limit (LEL).
• Rack Configuration: The monitor is available in simplex or redundant (TMR) 3500 rack configurations.
• Application Scenarios: It is particularly suitable for closed or confined spaces where flammable gases are used as fuel or are handled, pumped or compressed. Because once a leak occurs, the gas may accumulate and reach potentially explosive concentrations, and the detection and alarm of gas concentrations are critical to protecting personnel and equipment in the area. For example, the enclosure around a natural gas-powered industrial gas turbine, a hydrogen pipeline compressor or a compressor operating room are all confined spaces where flammable gases may accumulate.
• Redundant Configuration Requirements: When used in a Triple Modular Redundant (TMR) configuration, hazardous gas monitors must be mounted adjacent to each other in groups of three. In this configuration, two voting methods are used to ensure accurate operation and avoid single points of failure.

Specifications:
Input
Signal: Three-wire heated catalytic bead, single-arm resistor bridge.
Sensor Constant Current: 290 to 312 mA at 23°C; 289 to 313 mA at -30°C to 65°C.
Sensor Normal Range: Detects open circuit conditions in sensor and field wiring.
Sensor Cable Resistance: 20 ohms maximum per bridge arm.
Input Impedance: 200 kOhms.
Power Consumption: 7.0 Watts typical.
External Sensor Power Supply: +24 VDC with voltage swing of +4/-2 VDC at 1.8 Amps.
Monitor Alarm Inhibit Function: Contact closure inhibits monitor alarm.
Voltage: +5 VDC typical.
Current: 0.4 mA typical, 4 mA peak.