COMET H5521 – WebSensor CO₂, Cable Probe 0–10,000 ppm, NDIR, 2 Relay Outputs

COMET H5521 – Ethernet CO₂ Sensor with External Cable Probe 0–10,000 ppm, NDIR, 2 Relay Outputs

The COMET H5521 is a professional Ethernet CO₂ sensor with an external cable probe and two relay outputs – the smart solution for precise CO₂ monitoring and direct control in offices, schools, conference rooms, server rooms, production halls, hospitals, theatres, or any environment where air quality must be actively maintained. Thanks to its flexible 1-meter probe cable, the measurement point can be optimally positioned – ideal for ventilation ducts, confined spaces, or remote measurement locations.

The maintenance-free dual-wavelength NDIR sensor with patented auto-calibration measures CO₂ extremely accurately in the range of 0 to 10,000 ppm (±(100 ppm + 5% of reading) at 25 °C and 1013 hPa). The sensor automatically compensates for aging – no field calibration required – ensuring long-term stability and reliability. CO₂ values are displayed on the integrated screen or indicated via a color LED, instantly visible to any room occupant. An additional adjustable acoustic alarm (buzzer) warns in case of threshold exceedance.

The two relay outputs (max. 50 V / 2 A / 60 VA) can be freely configured by CO₂ thresholds – ideal for direct control of fans, humidifiers, dehumidifiers, alarms, dampers, or emergency shutdowns. Via Ethernet (RJ45), the sensor integrates seamlessly into networks – with direct connection to COMET Cloud (3 months free, then 1 credit/year) for charts, exports, alarms, and remote access via app or browser. Alternatively, Modbus TCP, SNMP, JSON, or XML can be used for integration into your own BMS/SCADA/IoT solution.

The robust housing (IP30 electronics, IP65 probe) and wide operating temperature range from –30 to +80 °C make the H5521 a reliable partner for continuous industrial or environmental monitoring – indoors or outdoors. No dedicated server is required – COMET Cloud handles all data processing and alarms.

Why the COMET H5521 is the professional CO₂ sensor with relays:

• External cable probe – maximum flexibility for measurement points
• Extended CO₂ range 0–10,000 ppm – for demanding applications
• High-precision NDIR sensor – patented auto-calibration
• 2 relay outputs – 50 V / 2 A – for direct control
• Ethernet interface – direct network integration
• COMET Cloud included – 3 months free, then low-cost credit
• Modbus TCP, SNMP, JSON, XML – compatible with third-party systems
• Color LED + acoustic alarm – instant on-site warning
• Integrated display – live values immediately visible
• Remote alarm function – E-mail, SNMP Trap, Syslog
• IP65 probe – suitable for humid and dusty environments

Technical Data H5521:

• CO₂ measuring range: 0 to 10,000 ppm
• CO₂ accuracy: ±(100 ppm + 5 % of reading) at 25 °C and 1013 hPa
• Resolution: 1 ppm
• Measuring interval: 15 s
• Probe cable length: 1 meter (standard)
• Relays: 2 × max. 50 V / 2 A / 60 VA
• Interface: Ethernet (RJ45)
• Cloud: COMET Cloud (3 months free)
• Protocols: WWW, Modbus TCP, SNMPv1, SOAP, XML
• Alarm protocols: E-mail, SNMP Trap, Syslog
• Power supply: 9–30 V DC (PoE optional)
• Operating temperature: –30 to +80 °C
• Protection rating: IP30 electronics, IP65 probe
• Dimensions: 136 × 150 × 45 mm
• Warranty: 3 years

Perfectly suited for:

• Schools, kindergartens & lecture halls
• Offices & open-plan workspaces
• Conference & meeting rooms
• Server rooms & data centers
• Hospitals & healthcare facilities
• Production & storage halls
• Demand-controlled ventilation systems
• Smart building & energy management

Setup – done in minutes

Connect the network and power cables, position the probe at the desired location, assign an IP address via DHCP or manually – done! The integrated web interface guides you through setup and relay programming. With COMET Cloud, you’re online within seconds – no server setup needed.

Summary:

• CO₂ transmitter with two relay outputs
• CO₂ measurement based on a dual-source, dual-beam principle
• Proven non-dispersive infrared (NDIR) cell ensures long-term CO₂ measurement stability
• The patented autocalibration compensates infrared source aging, guaranteeing reliability and long-term stability
• No regular on-site recalibration required
• CO₂ concentration displayed on the screen or indicated via a color LED

Scope of delivery:

• H5521
• User manual
• Traceable calibration certificate
• Free TSensor software for transmitter configuration
• COMET Cloud access for 3 months
• Power supply not included