COMET P8641 – 4-Channel PoE WebSensor for External Temperature/Humidity Probes

COMET P8641 PoE WebSensor 4-Channel T+RH 

The COMET P8641 is the high-performance PoE WebSensor (P-Line) with four channels for external temperature and humidity probes – the ultimate solution for comprehensive, precise multi-point monitoring in server rooms, technical rooms, warehouses, clean rooms, production facilities, climate chambers, or any location where multiple measurement points need to be monitored simultaneously. Thanks to Power over Ethernet (IEEE 802.3af), it requires only a single network cable for both data and power – installation is simpler, cleaner, and more cost-effective without separate power supplies.

The four external probes (DSxx series, sold separately) measure temperatures up to +105 °C and humidity from 0–100 %RH at different locations – e.g. four temperature points or two combined temperature + humidity probes. In addition to primary values, the P8641 automatically calculates all key humidity parameters: dew point, absolute humidity, specific humidity, mixing ratio, and specific enthalpy – all directly available via the integrated web interface or using Modbus TCP.

The large dual-line LCD displays current readings and can be switched off for continuous operation. Via Ethernet (RJ45) with PoE, the sensor integrates seamlessly into existing networks. Direct connection to the COMET Cloud (3 months free, then 1 Credit/year) provides charts, data export, alarms, and remote access via app or browser. Alternatively, Modbus TCP, SNMP, JSON, or XML can be used for your own SCADA/BMS/IoT system integration.

The robust housing and operational temperature range from –20 to +60 °C (probes up to +105 °C) make the P8641 a reliable partner for continuous operation – indoors or outdoors. PoE increases installation flexibility and energy efficiency, making it perfect for modern, low-maintenance multi-point monitoring.

Why the COMET P8641 is the professional 4-channel PoE WebSensor:

• Power over Ethernet IEEE 802.3af – power + data over a single cable
• 4 external channels – up to 4 temperature or 2 T+RH probes
• Ethernet interface – direct network connection
• COMET Cloud ready – 3 months free, then cost-effective
• Modbus TCP, SNMP, JSON, XML – open for third-party systems
• Large dual-line LCD – switchable off
• High precision – depending on probe, up to ±0.4 °C / ±2.5 %RH
• All humidity parameters integrated – dew point directly available
• Remote alarm function – email, SNMP Trap, Syslog
• IP30 protection – for indoor environments
• 3-year warranty

Technical data P8641:

• Temperature measuring range: –55 to +105 °C (depending on probe)
• Humidity: 0 to 100 %RH (depending on probe)
• Accuracy: depending on connected DSxx probe
• Resolution: 0.1 °C / 0.1 %RH
• Measuring interval: 2 s
• Interface: Ethernet (RJ45) with PoE IEEE 802.3af
• Cloud: COMET Cloud (3 months free)
• Protocols: WWW, Modbus TCP, SNMPv1, SOAP, XML
• Alarm protocols: Email, SNMP Trap, Syslog
• Display: Dual-line LCD, switchable off
• Power supply: PoE IEEE 802.3af or 5 V DC
• Operating temperature: –20 to +60 °C
• Protection rating: IP30
• Dimensions: 88 × 74 × 39.5 mm
• Weight: approx. 135 g
• Warranty: 3 years

Perfectly suited for:

• Building automation & BMS systems
• Data centers & server rooms
• Warehouses & production halls
• Technical & heating rooms
• Clean rooms & pharmaceutical production
• Multi-point monitoring
• Installations without separate power supply
• Integration into existing networks

Installation & commissioning – completed in minutes

Mount the device, connect the PoE network cable, and place up to four probes – done! The integrated web interface guides you through setup. With COMET Cloud, you are online in seconds – no additional power supply required.

Summary:

• Four-channel P-Line WebSensor with PoE (Power over Ethernet)
• Supports temperature and humidity probes
• Remote alarm function

Scope of delivery:

• P8641
• User manual
• Traceable calibration certificate
• Free TSensor software for transmitter configuration
• COMET Cloud for 3 months
• External probes are not included