X2-SDL Submersible Data Logger

X2-SDL Submersible Data Logger

The X2-SDL is a rugged, self-powered data logging and telemetry system for deploying environmental sensors in or near water without fear of accidental flooding.




The X2-SDL 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.

submersible connections

Underwater Connectors

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

long deployment data logger

Extended Battery Life

The X2-SDL operates for months on sixteen D-cell alkaline batteries. For longer deployments, extra alkaline battery packs and solar charging options are available.

cloud data


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

cellular, radio and satellite telemetry

Communication Options

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

water and weather sensors

Measurement Versatility

The X2-SDL 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, RS-485 and RS-232.

unattended deployment data logger

Buoy Integration

The CB-50 data buoy is designed to accommodate the NexSens X2-SDL submersible data logging system for unattended deployment in lakes, rivers, and coastal waters.

Tech Specs

Material: PVC body with Acetal battery lid
Weight: 12.0 lbs. without batteries; 16.6 lbs. with batteries
Dimensions: 5.5” (13.97 cm) diameter; 17.3” (43.94 cm) length (antenna length varies by model)
Internal Power
: 16 user-replaceable D-cell alkaline batteries
External Power Requirements
: 5-16 VDC +/-5% (Reverse polarity protected)
Current Draw (Typical @ 12VDC): Low power sleep: 350uA; Active: 45mA; Cellular Transmitting: 300mA; Iridium satellite transmitting: 170mA
Peak Current: Power supply must be able to sustain a 500mA 1-second peak current (@ 12V)
Operating Temperature: -20C to 70°C
Rating: Submersible to 200 ft. (requires SDL-CAP on telemetry models)
User Interface: RS-485 direct to CONNECT Software, WQDatalive Web Datacenter
Data Logging: 256MB microSD card (expandable up to 4GB)
Data Processing: Parameter level polynomial equation adjustment; Basic & Burst Averaging (min, max, standard deviation, and raw data available)
Real Time Clock (RTC): <30sec/month drift1; Auto-sync weekly2; Internal backup battery
Log Interval: User configurable from 1 minute (10 minute default)3; Unique interval per sensor
Transmission Trigger: Time-based, Selective parameter upload option
Sensor Interfaces: SDI-12, RS-232 (3 Channels), RS485
Sensor Power: (3) independent switches from input supply4,5
Built-in Sensors: Temperature (-40C to 85C, 0.1C resolution, ±0.3C accuracy); Humidity (0% to 100%, 0.1% resolution, ±4% accuracy from 5 to 95% RH & -20 to 70C); Battery voltage; System & sensor current
Sensor Ports: (3) 8-Pin for Sensor Interface (RS-232, RS-485, SDI-12, Switched Power, GND)
Power Port: (1) 6-Pin for Power and Communication (Primary/Backup Input, RS-485 Host, GND)
Telemetry Options: 4G LTE cellular, CAT-M1 cellular, Iridium satellite
Antenna Port: Type N female

1Assumes 25ºC operating temperature
2Requires the X2 to be connected to the internet
3Minimum log interval dependent on sensor limitations and processing time
4Cumulative concurrent current limit of all three channels is 2A
5Logger power supply must be able to support current requirements of sensors


Can the X2-SDL data logger be deployed as-is, or does it need to be secured in place?
The X2-SDL data logger is available as a standalone package that can be fully submerged for extended periods of time. Mounts are available for underwater structures and instrument cages. For applications requiring wireless telemetry, the logger is typically secured above water on a fixed structure (stream bank, piling, etc.) or housed inside a CB-50 data buoy.
Are any sensors included with the X2-SDL?
The X2-SDL data logger integrates a temperature and humidity sensor for internal monitoring and diagnostics. It also measures and logs alkaline battery voltage so users can plan for maintenance trips to swap batteries. The logger has three native sensor ports available for external 12 VDC digital sensors including water quality, water level, weather, soil, etc. Two-way and four-way sensor splitters are available to increase the number of sensors that the logger can simultaneously support.
What auxiliary power options are available for the X2-SDL submersible data logger?
The X2-SDL data logger includes a 6-pin auxiliary power port compatible with the SBP500 submersible battery packs, SP-Series solar power packs, or any user-supplied 5-24 VDC power source.

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