NexSens X2-SDL Submersible Data Loggers

The X2-SDL Submersible Data Logger is a rugged, self-powered data logging system with optional Wi-Fi, cellular, satellite, or radio communications.


  • Three sensor ports for connection to industry-standard digital sensor interfaces
  • Powered by (16) D-cell alkaline batteries or optional solar power pack
  • Withstands extreme wave action, floods, and periodic & long-term deployment underwater
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NexSens X2-SDL Submersible Data Loggers

The X2-SDL Submersible Data Logger is a rugged, self-powered remote data logging system for deploying environmental sensors in lakes, streams, rivers, wetlands, coastal waters, sewers, and culverts without fear of accidental flooding. The system is configured with three sensor ports for connection to industry-standard digital interfaces including RS-485, RS-232 and SDI-12. Additional sensor inputs are available through the use of adapters. Each sensor port offers a UW receptacle with double O-ring seal for a reliable waterproof connection. Unlike many data loggers, the X2-SDL is truly submersible. The housing and battery compartment are completely sealed and waterproof.

When it comes to field ruggedness, the NexSens X2-SDL is in a class of its own. The housing is constructed of impact-resistant PVC and includes two elastomer bumpers for long-term deployment in close-fitting pipes and buoy ports. Internal circuit boards and communication modules are shock mounted and all access ports incorporate redundant sealing. The X2-SDL withstands extreme wave action, drops, floods, periodic & long-term deployment underwater, and more. When fitted for wireless remote communication, the Wi-Fi, cellular, satellite, and radio antennas are also waterproof.

The X2-SDL can be powered autonomously by sixteen D-cell alkaline batteries. Optional solar power kits provide long-term continuous operation and solar charging. Common sensor connections include multi-parameter sondes, water quality sensors, temperature strings, ADCP's, water level sensors, and weather stations. Optional integrated Wi-Fi, cellular or satellite telemetry modules offer real-time remote communications via the WQData LIVE web datacenter. There, data is presented on a fully-featured and easy-to-use dashboard. Other features include automated reports, alarms, push notifications and much more.

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: Wi-Fi, 4G LTE cellular, CAT-M1 cellular, Iridium satellite, 900 MHz radio, 2.4 GHz radio
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

Questions & Answers
How long is the battery life for this logger?
The battery life is dependent on what sensors are connected, the measurement interval, and the transmit interval (if applicable). Contact us for a custom power budget tailored to your specific application.
Can more than 3 sensors connect to this logger?
Yes, UW-2W and UW-4W splitters can accommodate more 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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