SDL500 Submersible Data Logger: The NexSens Technology workhorse

NexSens SDL500 Submersible Data Logger

NexSens Technology’s SDL500 data logger is designed to withstand harsh conditions. Fitting securely into NexSens’ buoys, the fully submersible logger is an ideal choice for system deployments in lakes, streams or rivers. It features five sensor ports, multiple telemetry options and watertight reliability.

“The SDL500 is really the workhorse of the buoy-based systems that we offer,” said Doug Nguyen, chief engineer for NexSens Technology. “It supports sensors, telemetry and data collection and can go down to 200 feet. Some SDLs have even been deployed under ice.”

The logger was designed for deployment in NexSens’ buoys, enhancing versatility in system design. The buoys are designed for years of service in lakes, rivers or coastal waters. Systems are available with up to 1500-pound net buoyancy and optional solar panels provide long-term power. Deployment pipes and instrument cages support and organize sensor configurations.

Sensors interface with the SDL500 through industry-standard communication protocols like SDI-12, RS-232, RS-485 and analog. Common sensors like water quality sondes, temperature strings and weather stations are a quick addition. NexSens connectorizes all sensor cables to use watertight plugs, making for a simple plug-and-play interface.

“A double o-ring seal protects the inner workings of the logger, but it’s just as important that the sensor connections are watertight,” said Nguyen. “So that’s also a key advantage to our connectors.”

The SDL500 logs data from various sensors based on user-defined intervals. All data are displayed in iChart software, which offers the industry’s largest device library. The library contains drivers for YSI, Hach, Vaisala, Lufft and many other manufacturers.

Data are sent via cellular, radio or satellite telemetry. Cellular is the most common choice, says Nguyen, followed closely by radio. If needed, NexSens’ iChart software can send alerts via email or text message when parameter levels exceed predefined thresholds.

The software can also push data to a NexSens WQData web datacenter, which allows project personnel to access data at any time from a web browser. The online datacenter makes it easier for multiple project managers to share and manage data, says Nguyen.

“We’ve found that different projects have different needs. The telemetry options make monitoring possible in even secluded locations. Customers have used the satellite option all over the world,” said Nguyen. “And WQData is a popular option that makes it easier to share data publicly.”

Nguyen has worked on many projects using SDL500 submersible data loggers and has seen them deployed for bridge scour monitoring, in flood alert systems and along rivers where dredging is taking place.