COMET U0843M – IoT Wireless Datalogger with 2G Modem, 2 x External Pt1000 Sensors, 2 Binary/Dual-State Inputs

COMET U0843M – IoT Wireless Datalogger with 2G Modem, 2× External Pt1000 Probes (-200 to +260 °C ±0.2 °C), 2 Binary/Two-State Inputs, SMS/JSON Alarm 

The COMET U0843M is a high-performance IoT wireless datalogger with an integrated 2G modem (Quad-Band GSM/GPRS) – a self-contained and autonomous solution for remote monitoring and long-term recording of temperature via two external Pt1000 probes plus two binary/two-state inputs (e.g. door/window contact, switch, relay status, pulse). Whether for cold chain, warehouses, climate chambers, cold rooms, transport, pharmaceutical production, food industry, server rooms, machine monitoring, or remote locations – the U0843M sends immediate SMS and JSON alarms over GPRS when limits are exceeded or a state change occurs. Regular JSON data transfer to COMET Database or COMET Cloud (a complete monitoring, alarm, and analysis tool) can be configured. On-site alarms are indicated by LED, LCD, and buzzer. With a memory capacity of 500,000 readings (non-cyclic) or 350,000 readings (cyclic) and a traceable calibration certificate (EN ISO/IEC 17025), it is perfect for quality management, audits, temperature mapping, and status monitoring.

The two external Pt1000 inputs measure temperatures from -200 to +260 °C (±0.2 °C from -50 to +100 °C, ±0.2% of the measured value above, ±0.4% from -200 to -50 °C). The two binary/two-state inputs detect switching states (<0.4 V = Low, >2 V = High, max. 30 V DC) or potential-free contacts (resistance <10 kΩ = on, >300 kΩ = off, minimum duration 1 s). The acoustic and optical alarms provide immediate warnings when adjustable limits are exceeded or when a status change occurs. Min/max values are stored. The backlit LCD displays all channels simultaneously. The logger operates completely autonomously with its internal battery – no external power source required. Data download via USB-C to PC is supported. COMET Cloud: 3 months free, then 1 credit per year. The Quad-Band GSM modem (850/900/1800/1900 MHz) 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 maximum measurement accuracy from the factory. Configuration is intuitive via LCD or COMET Cloud. Whether used as a mobile logger in transport vehicles, as a stationary monitor in cold rooms, or as a central device in production – the U0843M impresses with precision, autonomy, 2G connectivity, binary inputs for state monitoring, and easy operation. The two Pt1000 inputs enable differential measurements (e.g., flow/return or product/ambient), while the binary inputs can monitor door/window/switch status.

Why the COMET U0843M is the best IoT 2G datalogger for 2× Pt1000 + 2 Binary Inputs:

• Integrated 2G modem (Quad-Band GSM/GPRS) – SMS/JSON alarm & data transmission without WiFi/LAN
• 2× external Pt1000 inputs – dual temperature measurement for differential or redundant operation
• 2× binary/two-state inputs – remote monitoring of door/window/switch/relay status
• 500,000 value memory – non-cyclic or cyclic
• COMET Cloud – complete monitoring, alarm & analysis (3 months free)
• Acoustic/optical alarm + LED – immediate on-site warning
• Wide measuring range – -200 to +260 °C (±0.2 °C core accuracy)
• Backlit LCD – simultaneous display of all channels
• Traceable calibration certificate included – EN ISO/IEC 17025
• Battery-powered autonomous operation – no external power required
• 3-year warranty – guaranteed COMET quality

Technical data U0843M:

• External temperature (Pt1000): -200 to +260 °C (±0.2 °C from -50 to +100 °C / ±0.2% above / ±0.4% from -200 to -50 °C)
• Resolution: 0.1 °C
• Binary/two-state inputs: <0.4 V = Low, >2 V = High (max. 30 V DC), potential-free contacts (<10 kΩ = on, >300 kΩ = off, minimum duration 1 s)
• Alarm: acoustic + optical + SMS/JSON via GPRS
• Memory: 500,000 readings (non-cyclic) / 350,000 readings (cyclic)
• Internal recording interval: 1 s to 24 h
• COMET Cloud recording interval: from 5 minutes
• Measurement/alarm interval: adjustable 1 s, 10 s, 1 min
• Display: backlit LCD
• Communication: 2G modem (Quad-Band 850/900/1800/1900 MHz, GPRS Class B) + USB-C
• Power supply: internal battery (operating time of several months/years depending on configuration)
• Operating temperature: -20 to +60 °C
• Protection rating: IP67 (device)
• Warranty: 3 years

Perfect for:

• Cold chain & transport monitoring (remote differential measurement)
• Warehouse and cold storage monitoring at remote locations
• Remote monitoring of doors/windows/switches
• Pharmaceutical and food production
• Climate chambers and incubators
• Product vs. ambient temperature (dual channel)
• Quality management & audits
• Autonomous long-term logging without external power

Installation and setup – done in minutes

Connect external Pt1000 probes and binary signals, insert a SIM card (if desired), activate the battery – done! Set up intervals, limits, and Cloud/SMS parameters, start logging – read data via COMET Cloud or USB-C. The backlit display and acoustic/optical alarm ensure safe and convenient operation. Calibration certificate included – ideal for audits and quality management.

Summary:

• The GSM datalogger is designed for recording two external temperature probes and two two-state inputs.
• When configured limits are exceeded, SMS and JSON messages can be sent via GPRS data connection.
• The measured values can be transmitted to the COMET Cloud, a comprehensive monitoring, alarm, and analysis system.
• Regular transmission of JSON messages to the COMET Database can also be configured; the sending interval is adjustable.
• Alarms are locally indicated via LED, LCD, and an integrated acoustic signal device.
• Data are stored in non-volatile electronic memory.
• Data can be transferred to a PC via the supplied USB-C cable.
• The GSM device includes a traceable calibration certificate with declared metrological traceability of standards according to EN ISO/IEC 17025.
• When purchasing a new IoT wireless datalogger with integrated modem, you receive 3 months of COMET Cloud free of charge; to continue using COMET Cloud for a full year, 1 credit is required thereafter.

Scope of delivery:

• U0843M
• User manual
• Traceable calibration certificate
• Battery
• Power adapter
• USB-C cable
• Full version of COMET Vision analysis software (free)
• COMET Cloud for 3 months
• SIM card not included
• External probes not included