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PLC 230 V AC wiht Fathom-X

I am looking for a PLC for industry that can perform the comunication in 230 AC.
Because its impossible if i use the fathom-x not yet?

What kind of communication are you trying to do? What are you trying to connect to and from, and what kind of information or signal are you trying to send/receive?

The Fathom-X is for ethernet communication, which is digital. It’s not a PLC, and also wouldn’t do anything useful with a 230V AC signal.
EDIT: See this comment below

Thanks for the information. Im trying to send digital signal and recived a video signal but i need do that in a 230v AC cable. Can you help me?
Sorry for my english and thanks.

No worries :slight_smile:

Yep, that’s how the BlueROV system is set up :slight_smile:

Do you mean you want to use a cable that is capable of handling 230V AC signals to send the existing digital communication signals, or do you mean you need to send 230V AC signals instead of the current digital communication ones?

  1. For the first option, the digital signals should send correctly over any twisted pair of wires that has a wire gauge (thickness) of 12-30 AWG, as specified in the fathom-X technical details section.
  2. If you need to actually send 230V AC signals instead of the current ethernet ones, you’ll need to buy (or make) a converter that can turn internet protocol packets into the type of signal that can be understood by what you’re trying to connect it to.Incorrect - see this comment. To help more in depth you would need to tell us what kind of signal you need to receive, or at least the device that you want to send the signal to.
    If you only want the video then it may not be possible to perform such a conversion, because the fathom-X + tether combination is currently used to transmit the video stream as well as the mavlink commands and telemetry, and possibly also data from other components like a sonar (if you have one installed).

okay, its the second option. Im going to connect a surface whit a Jetson nano of Nvidea. But i dont know how make that converter that can turn internet protocol.

I haven’t used a Jetson Nano before, but I’m pretty sure they don’t have anything to do with 230V AC signals. Do you have something else you’re trying to connect to that’s expecting a signal like that? How have you determined that a 230V AC signal is important for your application?

As mentioned in my previous comment, without knowing what device and signal protocol you’re needing/wanting to connect to it’s not possible to provide more in depth help.

I know but its the only way, i cant use the wifi of the jetson and the only cable is on 230V AC,
the signal cannot be changed because it must work with those conditions

I’m still new and they asked me to make this communication possible this communication, so i dont know the signal protocol but i think they used ethernet protocol

Hi @gon2000, I need to apologise for having misunderstood you, and because I had also misunderstood how the Fathom-X actually works.

My mistake

You’re asking about PLC, as in Power-Line Communication, which I hadn’t heard of before, so I was thinking about PLC as in Programmable Logic Controller (which are ruggedised relatively simple computers that are commonly used in industry).

Corrected Explanation

The Fathom-X uses the HomePlug AV protocol to convert ethernet communication into high-frequency AC waveforms, which are then decoded again on the other end by a paired HomePlug AV device. In the context of a BlueROV2, there is one Fathom-X on each end of one twisted pair of the tether - one inside the ROV, and one up at the top computer. In general, the HomePlug standards are an example of Powerline Communication, so they’re a type of PLC.

Fathom-X Suitability?

As for your actual question, the Fathom-X is intended for physically sending up to 200Mbits/s, and when sending packets using the internet protocol that ends up being about 80Mbits/s of actual data transfer, so they’re well-suited to sending things like streamed video and telemetry data.

I’m unsure of the voltage that the Fathom-X boards actually use on the tether (AC) side, but I don’t believe it to be as high as 230V, so if you need to interface with something that uses 230V then you’ll need to use a transformer to convert the output from a Fathom-X up to the required voltage, and to step down communication from the other direction into a voltage that won’t damage the Fathom-X or surrounding electronics. I have asked internally for confirmation on the communication voltage and will get back to you.


If you have a mains-level power line (e.g. >110V AC), it is probably preferable (and safer) to use a product that’s intended for that. Try searching online for “HomePlug Powerline adaptor” - there should be several options that can plug directly into a mains electrical socket and give you an ethernet port that you can plug into.

i’m waiting for you

I have the equipment to test this myself now, so just measured with an oscilloscope and the signal stayed within 10V peak-peak.

When I asked originally it wasn’t known what the signal driving voltage was - the QCA chip has both a 3.3v and 1.2v supply, and there’s a 3:1 step-up transformer, so it seems like the 3.3v is used for the signal (3.3V \times 3:1 = 9.9V).

I’ve been told the LX200V20 HomePlug converter board we use has a zero-crossing signal that isn’t connected in the fathom-X design, so even if you can step down to the appropriate voltage range it may not be possible to use with a true AC signal. It may be necessary to add a DC bias to offset an AC signal entirely into the DC voltage range, but I can’t guarantee this would work with or without a DC bias - we haven’t tried.

In case it’s of interest/relevance, the company that makes the LX200V20 is called RAKwireless, and they provide a design guide (including usage schematics) for it here. Note that the Fathom-X does not use the same schematic as their WisPLC evaluation board - our schematic is in our github.