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Connecting the Airmar CS4500 Ultrasonic speed sensor to N2K through a DT800

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Hi all,

I love the idea of an ultrasonic speed sensor because of all the issues everyone is aware of with physical paddle-wheels, but it looks like the Airmar NMEA2000 version of this isn't going to be forthcoming anytime soon.

However, I came across an Airmar "Smart Sensor" document entitled "Smart Sensors: Smarter and Well Connected" which says:

"• Smart™ depth transducers can accept input from Airmar's analog speed sensors which eliminates the need for an NMEA combiner and requires only one cable to be routed to display screen"

Basically they are saying that their analogue speed sensors can connect to an N2K network through a DT800 sensor. The example they give is an S650 speed sensor connected to a DT800.

Has anyone confirmed that this is possible?

Has anyone tried it with the CS4500 (Dan, that's you're cue :))?

I know that some of you have used Raymarine's Speed Pod to connect to N2K, but this would be a much cheaper and more elegant solution if it's true.

I've emailed Airmar with the same question, but thought it'd be interesting to get Panbots' views from the practical world.

Cheers, and Merry christmas all,


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  • I must be a genie in a lamp or something, seems when I check in here you just left a comment & rubbed my lamp.

    I would bet it works. After the output of the CS4500 passes thru the provided electronics box, the output is identical to a mechanical STW sensor.

    Do you have enough space to run all the wires? Output of CS4500 is a rather thick cable you will need to run to the included electronics interface above the water line, run a wire back to your DT800, and get a N2K wire in there as well. Not an issue if the DT800 also has an external electronics box, so that you need not run the N2K below the waterline to your sensor.

  • i too would be VERY interested in the results of that test - i just picked up a cs4500 myself, was despairing that to get it talking nmea2000 i'd have to lay out another couple of dollars for an interface, and have to buy a nmea2k depth on top of that, whereas a smart 2k triducer with conventional paddlewheel is only around $250.

    Paul, do you have any wiring diagrams of exactly how to hook the cs into the dt?


  • Dan,

    what is the issue with having nmea 2000 below the waterline? I can understand not wanting your wires soaking in the bilge, but I don't see how you could avoid the nmea 2000 drop lines running below the waterline - they have to run to the transducers, after all.


  • Hi Matt,

    I don't have any info other than a reference to it in this brochure from Airmar that I found on a web search:

    I've searched a lot and found nothing more, and my email direct to Airmar about it has not yet been returned (I guess it is Christmas).

    In the brochure it looks like there are two connectors from the DT800, and it references a 6 pin connector through which the DT800 will "accept input from Airmar's analog speed sensors....". It looks like you can connect it directly to the electronics inside the DT800.

    So I don't have a wiring diagram, or anything more, just a tantalising glimpse at a possibility.

    That's why I posted it here - I was hoping someone who is using the setup might be able to help.

    If you learn anything, please do post it here.


  • Hi Dan,

    I have the same question as Matt about your reference to below the waterline.

    Is it that you are using an external sensor with the wiring external to the hull?

    I think the connection will need an extra connection to the internal electronics of the DT800. I have a DST800 on the boat, so will investigate that next week as we are out sailing for the New Year for a week.

    I'm glad that there are a number of Genie's like you (and the Panbo site generally) who run closer to the leading edge of useful tech and are willing to share your knowledge. It is interesting that you happen to have knowledge in a number of areas that I'm currently implementing - but I'm very glad for that because otherwise it'd take forever to figure this stuff out :)

    I do think it's a circle, and hopefully I can help some other people in another field - (anyone want to talk about LiFePO4 batteries?) :)

    I hope everyone reading this has a great New Year's celebration, and see you next year.


  • As we all know, the area around thru hull sensors can get wet, or even soaked.

    The CS4500 comes with a small box of electronics intended to be installed in a nice dry place away from the cs4500 ultrasonic sensor itself. A thick cable from the cs4500 sensor runs to this box, as does power, the output of the box is identical to an analog paddle wheel.

  • What was the outcome ?

  • On which subject?

    N2K Speed Sensor - Available from Airmar with paddlewheel sensor.

    No Moving parts, e.g. CS4500 like - I see an announcement on the Airmar page, 2016 DAME Awards, 2017 Pittman Awards DX900+. I have not tested this.

  • Airmar now offers the UST800/850 Ultrasonic Speed Temp Smart Sensor with NMEA 2000 or 0183 output:

  • I'm using a Raymarine ITC-5 to convert depth from an old Airmar transducer and speed from the CS4500. Works like a champ.

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