COMET H7531 – WebSensor, Cable Probe, Temperature, Humidity, Pressure, Dew Point + 2 Relay Outputs

COMET H7531-2 – WebSensor with external cable probe for temperature –30 to +105 °C, humidity, pressure, dew point + 2 relay outputs 

The COMET H7531 is a professional Ethernet sensor with an external combined probe for temperature, relative humidity, and barometric pressure, featuring two powerful relay outputs. As a true remote thermometer–hygrometer–barometer with control function, it is the ideal solution for building automation, climate chambers, warehouses, clean rooms, production monitoring, greenhouses, or anywhere temperature and humidity measurement must be combined with direct control functions (fans, alarms, heaters, humidifiers, etc.).

The high-precision capacitive polymer sensor and the excellent barometric pressure sensor ensure top accuracy and long-term stability. The probe measures temperatures up to +105 °C and humidity from 0–100 %RH. In addition to primary values, the H7531 automatically calculates all key humidity parameters: dew point, absolute humidity, specific humidity, mixing ratio, and specific enthalpy – all directly available via the web interface or Modbus TCP.

The two relay outputs (max. 50 V / 2 A) can be freely programmed via thresholds, alarms, or binary states, making them ideal for direct control of fans, valves, signal lights, or emergency shutdowns. The large dual-line LCD displays all readings and relay statuses. Via Ethernet, the sensor integrates seamlessly into networks, including direct connection to the COMET Cloud (3 months free, then 1 credit/year) for graphs, exports, alarms, and remote access via app or browser. Alternatively, Modbus TCP, SNMP, JSON, or XML allow integration into your own BMS/SCADA/IoT system.

The robust housing and operating temperature range from –30 to +80 °C (probe up to +105 °C) make the H7531 a reliable partner for continuous operation. The cable probe allows optimal placement of the measurement point – ideal for confined or hot areas.

Why the COMET H7531 is the professional sensor with relays:

• External cable probe – flexible for difficult installation locations
• 3-in-1: temperature + humidity + barometric pressure – with high-grade barometer
• 2 relay outputs – 50 V / 2 A – for direct control
• Ethernet interface – direct network connectivity
• COMET Cloud ready – 3 months free, then low-cost
• Modbus TCP, SNMP, JSON, XML – open for third-party systems
• Large dual-line LCD – displays values and relay status
• Highest accuracy – temp. ±0.4 °C | humidity ±2.5 %RH | pressure ±1.3 hPa
• All humidity parameters integrated – dew point directly available
• Remote alarm function – e-mail, SNMP trap, Syslog

Technical Data H7531:

• Temperature range: –30 to +105 °C (±0.4 °C)
• Humidity: 0 to 100 %RH (±2.5 %RH from 5–95 % at 23 °C)
• Dew point: –60 to +80 °C (±1.5 °C at T<25 °C and RH>30 %)
• Barometric pressure: 600 to 1100 hPa (±1.3 hPa at 23 °C from 800–1100 hPa)
• Resolution: 0.1 °C / 0.1 %RH / 0.1 hPa
• Probe cable length: depending on selected version
• Relays: 2 × max. 50 V / 2 A
• 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: IP65 (probe)
• Warranty: 3 years

Perfect for:

• Building automation and BMS systems
• Data centers and server rooms
• Clean rooms and pharmaceutical production
• Food storage and cold rooms
• Museums, archives, and repositories
• Production monitoring with control function
• Climate chambers and drying systems
• Meteorological stations

Mounting & Commissioning – done in minutes

Mount the electronic housing, place the probe at the desired measuring point, connect network cable and power, wire the relays – done! The integrated web interface guides you through configuration. Online in seconds via COMET Cloud – no server required.

Available Versions:

• Cable length 1 meter
• Cable length 2 meters
• Cable length 4 meters

Summary:

• Ambient temperature, relative humidity, and air pressure with two relay outputs
• The H7531 sensor provides online monitoring of temperature and relative humidity in environments without aggressive substances
• Three binary inputs allow detection of two-state signals
• Two relay outputs allow control of external devices
• The high-precision capacitive polymer sensor ensures excellent long-term calibration stability and top accuracy
• Measured values are converted into various humidity parameters: dew point, absolute humidity, specific humidity, mixing ratio, and specific enthalpy

Scope of Delivery:

• H7531 – probe cable length as selected above
• User manual
• Traceable calibration certificate
• Free TSensor software for transmitter configuration
• COMET Cloud for 3 months
• Power supply not included