Navionics boating app for autopilot control

Discussion and support for the Nmea2Wifi multiplexer - a 2-input Nmea 0183 wifi multiplexer.
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Alfredive
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Joined: Wed Mar 25, 2020 10:46 am

Navionics boating app for autopilot control

Post by Alfredive » Fri Jun 12, 2020 6:21 am

Hi Luis and friend of forum.
Is it possible to control my Raymarine s1000 pilot with Navionics boating app through the you of nmea2wifi multiplexer? I am not sure of that...

Luis Sa
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Re: Navionics boating app for autopilot control

Post by Luis Sa » Fri Jun 12, 2020 11:04 pm

Hello,

Thank you for your question. I must confess that I never tried but I received feedback of users saying yes. Actually that was the reason why I made the multiplexer bidirectionally. Note that the autopilot needs to accept Nmea0183 sentences. I am not sure which applications are best to send data to the autopilot. I also suggest to use TCP for that direction and UDP on the reverse (multiplexer to laptops or smartphones).

Also if data for the autopilot goes on burts and the baud rate is low (4800) it can happen that some long sequences like (RMC for GPS data) can fill the output buffer on the P3 output (NMEA2WIFI) or P5 (in the case of NMEA4WIFI). In the case of of the NMEA4WIFI you cause filtering to avoid buffer overflow. In the case of the NMEA2WIFI I have an unpublished firmware that when the output buffer on the P3 output gets full, the multiplexer waits a bit until the data goes out (instead of dropping it as it is the default).

Regards, Luis

Alfredive
Posts: 4
Joined: Wed Mar 25, 2020 10:46 am

Re: Navionics boating app for autopilot control

Post by Alfredive » Sat Jun 13, 2020 7:01 am

Dear Luis, Navionics support inform me that is not possible for now. I think in these way the app seems to be less useful. I also send you an e mail because I have some problem with the nmea2wifi multiplexer piloting my autopilot... when I send data through a1b1 and set a3b3 output to my s1000 Raymarine , the pilot doesn’t receive the nmea data showing no gps fix. If I connect wires plotter directly to autopilot, this works perfectly. It seems that the mutiplexer absorb some intensity of the signal or doesn’t output correctly the signal on p3(a3b3).
Any ideas?

Luis Sa
Site Admin
Posts: 535
Joined: Thu May 04, 2017 4:12 am

Re: Navionics boating app for autopilot control

Post by Luis Sa » Sat Jun 13, 2020 8:41 am

Hello,

This weekend I will write here about a possible solution.

Regards, Luis

Luis Sa
Site Admin
Posts: 535
Joined: Thu May 04, 2017 4:12 am

Re: Navionics boating app for autopilot control

Post by Luis Sa » Sat Jun 13, 2020 9:54 pm

Hello,

I will use an email conversation with an user (Geoff) to explain how to avoid possible errors when using the multiplexer to control an autopilot.

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Hi, Luis, I am using the NMEA2WIFI on my yacht in New Zealand. 
Source of GPS is Vesper 6000 AIS Transponder connected to multiplexer input #2 at 38400 baud. 
The multiplexer output #3 goes to Raymarine ST2000+ Autopilot and also to NASA Marine GPS Repeater at 4800 baud.
The laptop is using OpenCPN v 5.0 on Windows 10.   
I have configured the NMEA2WIFI to send data to the Laptop on UDP port 2000 and to receive data from the Laptop on TCP port 10110 and connect TCP to output #3. The OPenCPN has filter set on output to transmit only RMB, RMC and GSA.
I am testing the output #3 data with PUTTY.
The system works OK but I notice that even though OpenCPN is sending ECRMC sentences they are not appearing on the multiplexer output.
Please refer to the attached screenshots. Is there any reason why this is happening? Cheers, Geoff
My response was:

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Hello Geoff, Nice to hear from you again. 
When the last character of each sentence arrives at the "TCP input", an attempt is made to put the whole sentence in the P3 output buffer. The buffer has a total size of 128 characters. It is a FIFO buffer. The attempt consists on reading the available space on the buffer. If that space is equal or larger than the size of the received sentence, the sentence is placed in the buffer. Otherwise, it will be lost. This is how data is placed in the buffer. 
At the same time, data is taken out from the buffer and output on P3. This happens at 4800 baud. You may be losing data if the rate it arrives is greater than the rate it is send out. 
Please try to reduce the arriving rate by adjust it by filtering at the OpenCPN end. Please confirm to me if what I am saying is correct. Regards Luis 
Then I received this:

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Hi Luis, As you can see on the OpenCPN I have already filtered outgoing sentences to limit to the essentials; RMB, RMC and GSA. The AIS sentences are in orange which means they are are filtered and dropped by OpenCPN and not output on TCP. Only the sentences in blue are output.
I noticed that when I included APB and XTE sentences to be output this caused more sentences to be dropped by the NMEA2WIFI.   
Does the NMEA4WIFI have a bigger buffer for the oncoming TCP? Or is it still 128 characters same as NMEA2WIFI? Does it process the sentences any faster? Cheers, Geoff
One more email from me:

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Hello, The size of the buffer is not important that much. If the rate of taking out (reading) data is less than the rate that data is written into, the buffer will get full, sooner or later. A big buffer would only retard the problem. Also processing speed will not solve the problem. The problem will be the same on the Nmea4Wifi. I wonder if you can set a slower rate at the origin. 
Having said that,  I also wonder if the laptop sends the TCP data in burts. In that case a larger buffer could help. And in that case the Nmea4Wifi multiplexer could be a solution. Data coming on P2 could go directly to the serial output without travelling through the tablet (going through UDP and coming through TCP). You would use filtering on the serial output (P5) to block AIS. These are my thoughts about the problem. Sorry for assuming that the orange sentences were being transmitted. Regards Luis 
and another from me

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Hello Geoff, You can find here:
https://www.vela-navega.com/nmea2wifi/v53/NMEA2WIFIV63G.bin
a firmware where I removed the check for the output buffer size on P3. This
size is 128 bytes and I could not find an easy way to increase it. Actually
I am not sure if it is an hardware buffer in which case it is fixed!
So when there is a "received TCP" sentence to be written in the P3 buffer
it will be always sent. If the buffer has size to accommodate the sentence
the CPU will continue the processing as the sentence is output by hardware.
However if there is no space in the buffer for the whole sentence the processor
blocks until space is made available (space increases as bytes are sent out).
Please check if this works for you. I think that the "block" should not affect the overall
performance of the multiplexer.
I wait for your feedback as this may affect other users (no one has call my attention
to this problem before). Regards Luis
It seems that the 63G firmware solved the problem because Geoff answered this:

Hi Luis

Good news!

I have tested the new v. 6.3G software and so far it appears to be working perfectly. I have attached the screenshot with the same configuration as previously used.

Also I have now included APB and XTE sentences on the OpenCPN output and they also are also passing perfectly though to the P3 output. The Raymarine ST2000+ Autotiller is now tracking correctly with the route activated in OpencPN.

Many thanks and good work!

Geoff

Alfredive
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Joined: Wed Mar 25, 2020 10:46 am

Re: Navionics boating app for autopilot control

Post by Alfredive » Sun Jun 14, 2020 5:03 am

Thanks Luis, I ‘ ll try this firmware and let you know....
thank you again

Alfredive
Posts: 4
Joined: Wed Mar 25, 2020 10:46 am

Re: Navionics boating app for autopilot control

Post by Alfredive » Sun Jun 14, 2020 8:59 am

It tried the firmware with no result. Probably it can’t be fixed.
FE0B3E99-C7E4-4953-9C9F-2441FCBE3F16.png
480E84E9-AD78-4933-B19F-0DFE8555459D.png
I tried to send p1 to p3 with no output data

trozman
Posts: 1
Joined: Thu Apr 22, 2021 7:29 pm

Re: Navionics boating app for autopilot control

Post by trozman » Fri Apr 23, 2021 9:03 am

Hi Luis,

I have module NMEA2WIFI and I have already tried to connect my Raymarine ST2000+ pilot over P3 output 4800 like Geoff described and I have read all your forums that could help me with settings. I have tried all change port number TCP and UDP I also tried with 192.168.15.1 and so on. The problem is that Navionics won't connect or transmit to NMEA2WIFI (no blue led on output P3). My firmware is 64 and I have only connected my ST2000+ over Nmea on P3 output. Can you or Geoff please send me pictures how did you connect ST2000+ and settings of NMEA2WIFI module and settings on NAVIONICS app. Thanks

Luis Sa
Site Admin
Posts: 535
Joined: Thu May 04, 2017 4:12 am

Re: Navionics boating app for autopilot control

Post by Luis Sa » Sat Apr 24, 2021 10:07 pm

Hello,

Unfortunately I have no personal experience in using the multiplexer with autopilots. I just briefly read the ST2000 manual and it is indeed controlled by nmea0183 sentences. However I do not know how Navionics can output data. I only know Navionics which runs on my Android and receives sonar data plus AIS targets and displays them on the map. Geoff, as I could understand, was controlling the autopilot from OpenCPN (not Navionics).

Maybe someone can clarify this. Or you could send an email to Geoff using the forum (I think it is possible for registered users).

Sorry for not being able to help you further,

Regards, Luis

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