Web-Thermo Hygrometer

Precise climate monitoring with the Web Thermo-Hygrometer from Wiesemann & Theis

The Web Thermo-Hygrometer from Wiesemann & Theis is a high-precision, network-capable measuring device for simultaneous detection of temperature (-40 °C … +85 °C) and relative humidity (0 … 100 % RH, permissible 0 … 95 % non-condensing).

It automatically calculates the dew point and is ideal for professional climate monitoring in server rooms, data centers, production halls, warehouses, museums, and offices. The device features a powerful data logger (up to 20 years storage capacity), an intuitive web interface, and supports modern Industry 4.0 protocols such as MQTT, REST, and OPC UA.

Thanks to Power-over-Ethernet (PoE), high interference immunity, and optional DAkkS calibration, it meets the highest requirements for reliability and integration. With a 5-year warranty and comprehensive alarm functions, the Web Thermo-Hygrometer is the optimal solution for Green IT, building technology, and sensitive climate environments.

Technical highlights at a glance

• Temperature: -40 °C … +85 °C
• Relative humidity: 0 … 100 % RH (permissible 0 … 95 % non-condensing)
• Automatic dew point calculation
• Integrated data logger: min. 12 weeks up to max. 20 years
• PoE (Class 1) or external power supply 12–48 V DC
• Support for MQTT, REST, OPC UA, Modbus-TCP, SNMP v3
• Up to 12 individual alarms (including dew point alarms)
• Dynamic integration via AJAX/JavaScript
• Optional DAkkS or ISO factory calibration with certificate
• 5-year manufacturer warranty

Precise temperature and humidity measurement with dew point

The Web Thermo-Hygrometer combines a high-accuracy temperature sensor (-40 °C … +85 °C) with a capacitive humidity sensor (0 … 100 % RH). From these values, the dew point is automatically calculated in real time – a key parameter for avoiding condensation damage in server rooms and control cabinets.

The permissible operating range is 0 … 95 % RH non-condensing, allowing reliable operation even in demanding environments.

Powerful data logger and cloud connectivity

The internal data logger stores temperature, humidity, and dew point depending on the sampling rate (15 s to 60 min) between 12 weeks and 20 years. The battery-buffered real-time clock remains synchronized even in case of power failure (NTP synchronization).

Measured data can be automatically uploaded via FTP, email attachment, or directly to the W&T Cloud – providing worldwide access to historical climate data at any time.

Modern Industry 4.0 interfaces

The Web Thermo-Hygrometer is fully prepared for Industry 4.0 and IoT:

• MQTT – direct connection to cloud and IoT platforms
• REST API – easy integration into custom web applications
• OPC UA – standard in automation technology
• Modbus-TCP – integration with PLC and SCADA systems
• SNMP v1/v2c/v3 – seamless integration into monitoring systems
• Syslog, TCP/UDP sockets, FTP, Sensobase (ODBC)

Current measurement values can be dynamically integrated into dashboards or building management systems via JavaScript (AJAX).

Flexible alarm system including dew point alarm

Up to 12 individual alarms can be freely configured – for temperature, humidity, and dew point (threshold, hysteresis, delay). When limits are exceeded, the device automatically sends:

• Emails (including periodic reports)
• SNMP traps
• Syslog messages
• MQTT publish
• TCP/UDP messages

The dew point alarm in particular offers reliable protection against condensation, corrosion, and short circuits in IT infrastructures.

Easy installation and reliable power supply

The device is preferably powered via Power-over-Ethernet (PoE Class 1, max. 3.84 W) – ideal for installation in ceilings, cabinets, or walls without a separate power line.

Alternatively, external power supply via 12–48 V DC through pluggable screw terminals is possible. The RJ45 network port is galvanically isolated and supports 10/100 MBit/s with Auto-MDIX.

Standards, calibration, and warranty

The Web Thermo-Hygrometer meets the highest quality standards:

• High interference immunity according to EN 61000-6-2
• Low emission according to EN 55032:2015 + A1 Class B
• Optional ISO factory calibration or DAkkS calibration with certificate
• 5-year manufacturer warranty

Typical applications

• Server room and data center monitoring (condensation protection)
• Network cabinets and IT infrastructure
• Production halls, warehouses, and archives
• Museums, libraries, and climate-controlled rooms
• Pharmaceutical storage and cleanrooms
• Offices and conference rooms
• Green IT projects for air-conditioning optimization
• Building technology and energy management

The Web Thermo-Hygrometer from Wiesemann & Theis is the ideal solution for anyone who needs to reliably monitor temperature, humidity, and the critical dew point.

Whether for condensation protection in data centers, as an IoT sensor using MQTT, or as part of complex building management systems via OPC UA – it impresses with its high precision, ease of use, and durable quality.

With optional DAkkS calibration, PoE power supply, and a 5-year warranty, it is the first choice for IT managers, facility managers, and system integrators.