COMET H3531P – Compressed Air Temperature, Humidity, and Dew Point Sensor with 2 Relay Outputs

COMET H3531P – Ethernet Sensor for Compressed Air up to 25 bar, Temperature –30 to +105 °C, Humidity, Dew Point, 2 Relay Outputs

The COMET H3531P is a professional Ethernet sensor specially designed for compressed air applications up to 25 bar, featuring an external hard-anodized duralumin probe for temperature, relative humidity, and dew point measurement. As a true remote thermometer-hygrometer for compressors, compressed air lines, pneumatic systems, dryers, or process air, it is the ideal solution for precise monitoring and control in industrial, workshop, automotive, food, or pharmaceutical production environments.

The high-precision capacitive polymer sensor ensures excellent long-term stability and accuracy even under pressure. The probe measures temperature up to +105 °C (±0.4 °C) and humidity 0–100 %RH (±2.5 %RH from 5–95 % at 23 °C). The dew point is calculated with high accuracy (±1.5 °C at +10 °C and higher). All humidity parameters (absolute humidity, specific humidity, mixing ratio, specific enthalpy) are available directly.

The two relay outputs (max. 50 V / 2 A) can be freely configured via thresholds, alarms, or binary states – ideal for direct control of dryers, valves, alarms, or compressor control. The large dual-line LCD displays all measured values and relay status. Via Ethernet, the sensor integrates seamlessly into networks – with direct connection to the 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 protocols can be used for your own BMS/SCADA/IoT solution.

The probe is designed for airflow up to 25 m/s (at 1 bar) or 1 m/s (at 25 bar) and is resistant to condensate and oil mist. The robust housing and operating temperature range from –30 to +80 °C make the H3531P a reliable partner for tough industrial environments. The 1-meter cable probe allows optimal placement in pipelines.

Why the COMET H3531P is the Professional Compressed Air Sensor:

• Special probe for compressed air up to 25 bar – hard-anodized duralumin
• External cable probe 1–4 m – flexible for lines & tight spaces
• 2 relay outputs – 50 V / 2 A – for direct control
• Ethernet interface – direct network connection
• COMET Cloud ready – 3 months free, then low-cost
• Modbus TCP, SNMP, JSON, XML – open to third-party systems
• Large dual-line LCD – displays values + relay status
• Highest precision – Temp. ±0.4 °C | Humidity ±2.5 %RH | Dew point ±1.5 °C
• All humidity parameters integrated – dew point directly available
• Remote alarm function – E-mail, SNMP Trap, Syslog

Technical Data H3531P:

• 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 +10 °C and higher)
• Probe pressure range: up to 25 bar
• Airflow: up to 25 m/s (1 bar) / 1 m/s (25 bar)
• Relays: 2 × max. 50 V / 2 A
• Probe cable length: as selected above
• 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 class: IP65 (probe)
• Warranty: 3 years

Perfectly suited for:

• Compressed air systems & compressors
• Dryers & pneumatic installations
• Industrial & process air monitoring
• Automotive & mechanical engineering
• Food & pharmaceutical production
• Building automation with relay control
• Quality assurance in compressed air
• Humidity & dew point control up to 25 bar

Installation & Commissioning – done in minutes

Mount the electronic housing, install the probe into the compressed air line (e.g. via 1/4" or 1/2" thread), connect network and power cables, wire the relays – done! The web interface guides you through setup. With COMET Cloud, you are online in seconds – no server required.

Available Versions:

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

Summary:

• Ethernet sensor for compressed air humidity and temperature with two relay outputs
• Temperature and relative humidity probe made of hard-anodized duralumin for compressed air up to 25 bar with cable
• Humidex display
• The H3531P sensor is designed for online monitoring of temperature and relative humidity in non-aggressive air environments
• Three binary inputs for detecting two-state signals provide an additional advantage
• Other devices are controlled via the two relay outputs
• The high-precision capacitive polymer sensor ensures excellent long-term calibration stability and highest accuracy
• Measured values are converted into additional humidity parameters: dew point temperature, absolute humidity, specific humidity, mixing ratio, and specific enthalpy.

Scope of Delivery:

• H3531P - 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