Problems with the Navionics APP and the NMEA datasets

[theo]

Hello everyone,

I have a problem with the interface and can't get any further.

I would like to display NMEA data in the Navionics app. I am feeding data from the radio (AIS and position) via NMEA 0183 and I want to feed depth from my depth gauge. So far so good. The position works, I can't test AIS due to the lack of boats in range, but I think that should work.

I only have my problems with the depth. There is a simulation mode in the interface, the depth works perfectly in the Navionics, only when I switch on my real data the Navionics does not recognize it. I have attached both datasets for you to compare, here you can also see that data is actually arriving at the tablet in real-time mode.

Can someone possibly help me there?

Would be great, thanks in advance....

Kind regards

Theo

[Maudie-IV]

Hi Theo

I'm coming at this from a position of very little knowledge, but:

the simulator script only includes a single depth sentence DBT (depth below transducer) whereas the live date both DPT (water depth) and DBT. Is this confusing the Navionics? Maybe you could try filtering out the DPT sentence in settings to see if this makes any difference.

As a matter of interest, what app did you run on your tablet or how else were you able to view the incoming data stream?

Maybe you have already found the answer to your problem. If so, please share!

Regards

Paul

[theo]

Hello, I've already tried dpt and dbt, but it still doesn't work. I found the problem, navionics absolutely needs the checksum at the end. I wrote to Luis and asked if he could build the function into his multiplexer. That the multiplexer automatically calculates the checksum and then appends it at the end if it is missing. He replied that he wanted to take a look. Maybe others have the same problem. The app for viewing is called "IAIS" by digitalyacht, but it's only available for iOS...

[dagnall]

Theo:
Luis' simulated data does include checksums for the simulation of 13 / 13.1ft DBT data.

I have found that Navionics can be "fussy" when trying to "synch".
I find TCP connection seemingly works easier, and so quickly set up my NMEA3 to simulate and send on UDP and TCP.
The TCP "synch" seemed to work better - or at least for me.
The app then showed TWO (??) depth displays and the simulated GPS and AIS targets.

I have no idea why it displayed the duplicated depth.. but it shows it got the data!

Please also see viewtopic.php?f=6&t=152&p=1065&hilit=na ... +udp#p1065
Where I noted that Navionics (at the time) needs 0.0.0.0 for UDP..
Not sure if this is still the case.. But that may also help!

Dagnall

[Luis Sa]

Hello Theo,

I am sorry for not coming to your email. Your problem is the following:

you have a depth sensor that transmits DPT nmea0183 messages. That sensor does not adds the checksum to those messages. You would like a custom version of the multiplexer that adds that checksum

Could we define the input port that you use for that sensor? I do not want to waste time to check if the arriving sentence is DPT on all the input ports. Better is also to fix the output port. Say that you connect the sensor to port P1 and that you direct P1 to UDP. If that is the case we could simply catch this situation and add a checksum. We even would not test if the sentence is DPT. What we would do is

- on outputting P1 through UDP we would test for the presence of the character * by the end of the sentence. If not present then we compute the checksum and append it to the sentence before sending it out by UDP.

Please tell if this is enough.

Regards, Luis

[theo]

Hello Luis,
thank you for your feedback.
Yes, that would be completely sufficient if it works at Port P1 and only with UDP.
Thank you in advance.
Regards Theo

[dagnall]

Theo.
I have added some experimental code in the #P1 input that checks $xxDBT messages.
If the message is a $xxDBT and is missing the checksum, it will try to add a correct checksum before sending the message (with checksum) onwards to whoever you choose.
It will not try to correct wrong checksums or DBT data on other ports.

A small and possibly confusing aspect of this is that the NMEA4WIFI "DEBUG" will only show the "corrected" NMEA data.

I have tested this with Navionics via UDP, and I do have some reservations- I think Navionics is prioritizing the DBT Feet, and does not check that the feet/meters/fathoms are consistent. But it should now show you some data.

It would be helpful if you can advise what depth sounder you have please, so I can look up the manual for reference.

You can test the revised sw by unzippng the attached

NMEA4Navionicstest.zip

(592.84 KiB) Downloaded 395 times

and uploading the "NMEA4.ino.bin" file from the ZIP.
see https://www.vela-navega.com/index.php/update for instructions.

Once uploaded you should see this header.

screenshot of header for V61

.

Please let us know how well this works for you and if you see any other issues.

Best regards
Dagnall

[theo]

Hello Luis and dagnall,
It works very well. Exactly what I needed. We are in Croatia right now, here I can test it perfectly.
thank you very much...
best regards
Theo

[dagnall]

Hello Luis and dagnall,
It works very well. Exactly what I needed. We are in Croatia right now, here I can test it perfectly.
thank you very much...
best regards
Theo

Theo,
Very glad this is fixed..
Can you let us know the exact name and type of your Depth Sensor, so that we can help anyone else with the same issue?
Dagnall