COMET U3120G – IoT Wireless Datalogger with 4G Modem, Internal Temperature and Humidity Measurement

COMET U3120G – IoT Wireless Datalogger with 4G Modem, internal T+RH (-20 to +60 °C ±0.4 °C / 0–100 %RH ±1.8 %), dew point, SMS/JSON alarm 

The COMET U3120G is a modern IoT wireless datalogger with an integrated 4G modem (LTE Cat 1, FDD/GSM/GPRS/EDGE) – an autonomous and network-independent solution for remote monitoring and long-term recording of temperature, relative humidity, and dew point using internal sensors. Whether for cold chains, warehouses, climate chambers, server rooms, greenhouses, offices, hospitals, archives, or remote locations – the U3120G immediately sends SMS and JSON alerts via 4G when preset limits are exceeded. Regular JSON data transmission to COMET Database or COMET Cloud (a complete monitoring, alarm, and analysis tool) can be configured. Local alarms are indicated by LED, LCD, and buzzer. With a memory capacity of 500,000 records (non-cyclic) or 350,000 records (cyclic) and a traceable calibration certificate (EN ISO/IEC 17025), it is ideal for quality management, audits, and ISO compliance.

The internal sensors measure temperature from -20 to +60 °C (±0.4 °C) and humidity from 0 to 100 %RH (±1.8 %RH). The dew point is automatically calculated (-90 to +60 °C, ±1.5 °C at T<25 °C and RH>30 %). The acoustic and optical alarm gives an immediate warning when freely adjustable thresholds are exceeded. Min/Max values are stored. The backlit LCD display is easy to read, the measurement rate (0.7 to 5 s) and display refresh rate are adjustable. The logger operates completely autonomously on an internal battery – no external power supply required. Data can be downloaded to a PC via USB-C. COMET Cloud: 3 months free, then 1 credit per year. The LTE FDD B1/B3/B5/B7/B8/B20 & GSM/GPRS/EDGE 900/1800 MHz modem ensures global coverage and stable data transmission.

The datalogger is maintenance-free, long-term stable, and comes with a 3‑year warranty. The included traceable calibration certificate guarantees the highest measurement accuracy from the factory. Intuitive configuration via LCD or COMET Cloud. Whether used as a mobile remote logger on construction sites, a stationary monitoring unit in buildings, or a central device in facility management – the U3120G stands out for its precision, autonomy, 4G connectivity, and ease of use. No external probe required – ready for immediate indoor measurement.

Why COMET U3120G is the best IoT 4G datalogger for T+RH:

• Integrated 4G modem (LTE Cat 1) – SMS/JSON alarm & data transmission without Wi‑Fi/LAN
• Internal T+RH sensors – ready to use without probe
• 500,000 data memory – non-cyclic or cyclic
• COMET Cloud – full monitoring, alarm & analysis (3 months free)
• Acoustic/optical alarm + LED – instant on-site warning
• Dew point & all humidity parameters – automatically calculated
• Backlit LCD – all values clearly visible at once
• Traceable calibration certificate included – EN ISO/IEC 17025
• Battery-powered for full autonomy – no external power required
• 3‑year warranty – guaranteed COMET quality

Technical data U3120G:

• Internal temperature: -20 to +60 °C (±0.4 °C)
• Internal humidity: 0 to 100 %RH (±1.8 %RH)
• Dew point: -90 to +60 °C (±1.5 °C at T<25 °C and RH>30 %)
• Resolution: 0.1 °C / 0.1 %RH / 0.1 °C dew point
• Alarm: acoustic + optical + SMS/JSON via 4G
• Memory: 500,000 values (non-cyclic) / 350,000 values (cyclic)
• Logging interval: 1 s to 24 h
• Measurement interval / display update: 0.7 to 5 s
• Display: backlit LCD
• Communication: 4G modem (LTE FDD B1/B3/B5/B7/B8/B20 + GSM/GPRS/EDGE 900/1800 MHz) + USB‑C
• Power supply: internal battery (lifetime depending on configuration – several months/years)
• Operating temperature: -20 to +60 °C
• Protection rating: IP20 (device)
• Warranty: 3 years

Perfect for:

• Cold chain & transport monitoring (temperature & humidity remotely)
• Warehouse and cold room monitoring
• Pharmaceutical and food production
• Server rooms and data centres
• Greenhouses & agriculture
• Offices, schools & hospitals (indoor air quality monitoring)
• Remote monitoring without on-site internet access
• Quality management & audits

Setup and operation – done in minutes

Activate the battery, insert the SIM card (if desired) – done! Set intervals, limits, and Cloud/SMS options, start logging – read data via COMET Cloud or USB‑C. The backlit display and acoustic alarm ensure safe and convenient operation. Calibration certificate included – ideal for audits and quality management.

Summary:

• The 4G datalogger records temperature and humidity using integrated sensors
• When set limits are exceeded, SMS and JSON messages are sent via the 4G data connection
• Measured data can be transmitted to the online storage COMET Cloud, a complete monitoring, alarm, and analysis system
• Regular transmission of JSON data to the COMET database can also be configured; the transmission interval is adjustable
• Alarms are displayed locally via LED, LCD, and an integrated acoustic signal
• Records are stored in non‑volatile electronic memory
• Data can be transferred to a PC via the supplied USB‑C cable
• The 4G recorder includes a traceable calibration certificate ensuring metrological traceability according to EN ISO/IEC 17025
• When purchasing a new IoT wireless datalogger with integrated modem, you receive 3 months of COMET Cloud for free; for a full year of usage, 1 credit is required thereafter. 

Scope of delivery:

• U3120G
• User manual
• Traceable calibration certificate
• Battery
• Power adapter
• USB‑C cable
• Free full version of COMET Vision analysis software
• COMET Cloud for 3 months 
• SIM card not included