Seatalk - bogus values

Discussion and support for the Nmea2Wifi multiplexer - a 2-input Nmea 0183 wifi multiplexer.
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Moringen
Posts: 4
Joined: Tue Sep 22, 2020 7:07 am

Seatalk - bogus values

Post by Moringen » Tue Sep 22, 2020 9:43 am

Using the NMEA2WIFI connected to a SEATALK network.
When logging all the received values, I see some bogus values from the wind/speed/dept sensors.

The checksum is correct, I guess the error is on the SeaTalk side. All GPS messages are OK.

Some examples from the log.

Wind Speed and Angle, angle and reference are missing
2020-09-20 15:06:09,$VWVHW,,,,,3.30,N,,,*34.

Wind Speed and Angle, angle is too big.
2020-09-20 15:06:09,$WIMWV,31240.5,R,6.0,N,A*24

#Depth Below Transducer, sometimes give out very big values, int this example 4096 (2^12)
2020-09-20 13:56:17,$SDDBT,57.1,f,,,,*3E
2020-09-20 13:56:18,$SDDBT,56.8,f,,,,*36
2020-09-20 13:56:22,$SDDBT,57.3,f,,,,*3C
2020-09-20 13:56:23,$SDDBT,4096.0,f,,,,*36

Is there any sanity check on the received SeaTalk messages in NMEA2WIFI?

Regards
-Torgeir-

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

Re: Seatalk - bogus values

Post by Luis Sa » Tue Sep 22, 2020 10:11 am

Hello.

Could you please confirm which firmware version you have?

Regards, Luis

Moringen
Posts: 4
Joined: Tue Sep 22, 2020 7:07 am

Re: Seatalk - bogus values

Post by Moringen » Wed Sep 23, 2020 7:33 am

I'm using FW 62, I see that you have made changes on SeaTalk code for version 63, I will upgrade and do more logging.

Regards
-Torgeir-

Moringen
Posts: 4
Joined: Tue Sep 22, 2020 7:07 am

Re: Seatalk - bogus values

Post by Moringen » Wed Sep 23, 2020 8:28 pm

Changed to the newest firmware.

Still some bogus data.

Big variations in temperature. (Reare that temperature is transmitted two times in a sec)
2020-09-23 18:05:47,$IIMTW,0,C*3D.
2020-09-23 18:05:47,$IIMTW,33,C*0Dd
2020-09-23 18:05:52,$IIMTW,0.1,C*22

Wind angles on the exact same (insane) AWA but with 14nots difference in AWS in one sec.
2020-09-23 18:17:13,$WIMWV,2176.5,R,1.12,N,A*26
2020-09-23 18:17:14,$VWVHW,,,,,3.5,N,,*2E
2020-09-23 18:17:14,$WIMWV,2176.5,R,15.0,N,A*20
2020-09-23 18:17:15,$VWVHW,,,,,3.2,N,,*29

Maybe the tow ST60 instruments are talking at the same time on the bus?

-Torgeir-

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

Re: Seatalk - bogus values

Post by Luis Sa » Thu Sep 24, 2020 12:20 pm

Hello,

Could you please tell how you are getting those files with the converted values? If you suspect that there are 2 systems transmitting data on the bus, could you temporarily switch off (remove) once at a time to discard that possibility?

I may write a firmware for the Multiplexer so that instead of converting to mnea0183, it would just send the Seatalk datagram that it receives so that you could see what goes on the bus. But that would take me some time to accomplish.

The description of the Seatalk conversion is explained in very detail (possibly very confusing) in the forum for the 4 input multiplexer. The 2 and the 4 input multiplexers work in the same way with regard to Seatalk.

Best Regards, Luis

Moringen
Posts: 4
Joined: Tue Sep 22, 2020 7:07 am

Re: Seatalk - bogus values

Post by Moringen » Fri Sep 25, 2020 10:13 am

Hi Luis,

I don't think that two instruments are talking the same time anymore, since the gps messages always is clean. But I will try this.

I get the files with converted values from an esp32 that writes all received data to a mini sd card.

A firmware that forwards raw seatalk messages will be nice!

Best regards
-Torgeir-

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