The SDL V2 Submersible Data Logger is a rugged, self-powered data logging and telemetry system for deploying environmental sensors in or near water without fear of accidental flooding.



The SDL V2 is designed with impact-resistant PVC, two elastomer bumpers, shock-mounted electronics and redundant seals. It can withstand extreme wave action, floods and underwater deployment to 200 ft.

Underwater Connectors

All connections are made with a simple waterproof thread-in connector. This removes the complications and errors associated with connecting individual wires.

Extended Battery Life

The SDL V2 operates for months on sixteen D-cell alkaline batteries. For longer deployments, extra alkaline battery packs and solar charging options are available.


When communicating via wireless telemetry, measurement data streams directly to the WQData LIVE web datacenter.

Communication Options

Real-time telemetry options include cellular, satellite, and radio. All communication modules are securely housed within the submersible enclosure, and a waterproof antenna is integrated on the top of the device.

Measurement Versatility

The SDL V2 is configured with three sensor ports to interface with multi-parameter sondes, water quality sensors, temperature strings, Doppler velocity meters, water level sensors, and more. Supported sensor interfaces include SD-12 and RS-485.

Buoy Integration

The CB-50 data buoy is designed to accommodate the NexSens SDL V2 submersible data logging system for unattended deployment in lakes, rivers, and coastal waters.
Ports(3) UW8 ports for sensor connection; (1) UW6 port for host connection and external power
Host Interface(1) RS-485 (half duplex)
Sensor Interface(1) RS-485 (half duplex); (1) SDI-12; Optional RS-232 (via smart RS-232 to RS-485 adapter); Optional analog (via mV to RS-485 adapter)
Sensor Power(1) Switched 5 VDC, (1) Fulltime 12 VDC, (2) Switched 12 VDC
Sensor ProtocolsModbus RTU; NMEA 0183; SDI-12; GSI (via custom script)
Host ProtocolsModbus RTU; Terminal command interface
Log Interval1 minute to 24 hours; supports different intervals for different sensors concurrently
Real Time Clock (RTC)<30sec/month drift; Auto-sync weekly; Internal backup battery
Built-In SensorsTemperature (-40 to 85°C, 0.01°C resolution, ±2°C accuracy from -20 to 85C); Pressure (300 to 1100 mbar, 0.016 mbar resolution, ±4 mbar accuracy from -20 to 85C); Humidity (0-100%, 0.04% resolution, ±5% accuracy from 5 to 95% RH); Battery voltage; Current draw
Internal Memory256MB microSD card (expandable up to 32GB)
Internal Power(16) D-cell alkaline batteries
External Power Requirements5-24 VDC ±5% (Overcurrent and Reverse polarity protection)
Typical Current Draw (@12V)Low power sleep: 160uA; Active: 40mA; Cellular transmitting: 300 mA; Radio transmitting: 215mA; Iridium transmitting: 170mA
Maximum Depth200 ft.
Temperature Range-40 to +85°C
Dimensions5.5” (13.97 cm) diameter; 16.50” (46.36 cm) length (antenna length varies by model)
Weight11.0 lbs without batteries; 16.6 lbs with batteries
Remote CommunicationCellular; License-free 900MHz and 2.4GHz radio; Iridium satellite
Supported Cellular Modems2G/3G international; 3G North American; 4G LTE North American; LTE-M North America; (future LTE-M1 North America; NB-IoT Europe)
Certified Cellular CarriersAT&T, Verizon
Radio Range (Line of Sight)Low power: 2 miles; High power: 28 miles; Extended power: 60 miles
Radio TopologyPoint-to-Point; Star; Mesh