How do I digitise transducer data to use onboard?

DST-2 NMEA Depth, Speed & Temperature Module

Transducers and DST-2 basics

The market for transducers is vast, and can sometimes be a little overwhelming. With the addition of ‘smart’ transducers which convert to digital, and dual frequency transducers becoming more common, this only makes things more confusing.

Fortunately, our team have created an analogue to digital converter for your transducer, meaning you don’t need to go about lifting your boat out of the water and ripping your legacy transducer out just yet!

The DST-2 digitises depth, speed and temperature transducer signals into NMEA 0183 data to deliver best-in-class seabed tracking. It works with NMEA 0183 compatible devices, such as chart plotters, radars or an onboard PC.

So, how does it work?

The DST-2 generates a transmit pulse (of power/energy) that the transducer converts into sonar/acoustic energy, sending out a pulse of energy/frequency wave into the water. When that energy hits an object, a small amount might be reflected back to the transducer that can convert that energy back into a voltage signal, which the DST-2 can detect and convert into a digital representation of its “strength.”

The Depth Algorithm determines if that echo is false (i.e. a very large bucket of things like objects floating in the water, algae layers, air bubbles from the propeller, etc.) or if it’s actually the sea bed. The DST-2 then waits for more echoes before it can determine for sure where the sea bed is and what distance that is from the depth transducer.

Having an NMEA 0183 output from the DST-2 allows for the data to be shared in various ways to different places. For example, you can connect an Actisense NGW-1 to the DST-2 output, which enables the conversion of data to NMEA 2000, for display on an MFD (shown in the diagram below). Alternatively, the DST-2 output can be connected to an Actisense USG-2, with the data then sent to a PC Application.

DST-2 network diagram with NGW-1
DST-2 network diagram

To conclude…

With 150, 170 and 200 kHz models available, the DST-2 is compatible with a wide number of transducers. Combine this with the cost and time savings when compared to switching out for a new transducer, and it’s easy to see why the DST-2 is such a useful product.