environment.outside.pressure appears with two different sources

[wcbonner]

I've had a problem with the data from my barometer on my N2K network in that it is only putting data into my influxdb at kPa resolution instead of the Pa that the device is reporting. I thought the problem was pushing the data to Influx and opened an issue there tkurki/signalk-to-influxdb#73, but after communication with the author i have spent a lot more time staring at the web browser and my SignalK data browser screen.

The data that I'm interested in is environment.outside.pressure and I realized that when it's displaying digits other than 00 in the least significant digits, it's reporting it's source as 1.116 (130314) but it switches to data with 00 in the least significant digits and changes its source to 1.116 (130311)

for example:

Path	Value	Units	date	Source
environment.outside.pressure	101715	Pa	date	1.116 (130314)
environment.outside.pressure	101700	Pa	date	1.116 (130311)
environment.water.temperature	313.15	K	date	1.115 (130311)

Only a single item is displayed at a time, and it switches between them. Also, while my water temperature reading is significantly incorrect, it's showing up as the same 130311 at a different source.

I have a Yacht Devices Digital Barometer YDBC-05 https://www.yachtd.com/products/barometer.html directly on my N2K network.
The Temperature, Wind, Water Speed are from raymarine seatalk devices and connected to the N2K network via a Raymarine Seatalk-Seatalkng Converter https://www.raymarine.com/en-us/our-products/networking-and-accessories/seatalk-ng-and-nmea-2000/seatalk-1-to-seatalk-ng-adaptor-kit

All of the old devices on the seatalk adapter report their source as 1.115

Has anyone seen this problem before and have a solution to get rid of the incorrect reading of 130311 as environment.outside.pressure?

[sbender9]

Since both PGNs come from the same source, there's no easy way to filter the bad one out (path-filter plugin). I think it could be done with node-red. I can look into that further if you want to try that route.

You can also configure the YDBC-05 not transmit pgn 130311

[wcbonner]

Since both PGNs come from the same source, there's no easy way to filter the bad one out (path-filter plugin). I think it could be done with node-red. I can look into that further if you want to try that route.

You can also configure the YDBC-05 not transmit pgn 130311

But shouldn't 130311 be recorded as a temperature instead of pressure?

I thought that part of the source was what tells the receiver what the data is.

I agree that the barometer shouldn't be broadcasting temperature.

I was just rereading the yacht devices manual. I guess I don't understand PGNs. In page 28 it says the factory default for the barometer is to send 130310, 130311, and 130314.

I should be able to disable the 130311 PGN by sending the command YD:PGN 130311 0

I'll just have to figure out how to do that because currently my only computer connection to the n2k bus is my Pi with the Pican-m hat.

[sbender9]

The 130311 pgn can include temperature, humidity and pressure. A PGN can include many different data points. You can find details about different PGNs here: https://canboat.github.io/canboat/canboat.html#pgn-list

The barometer is not sending temperature, something else is.

In the source 1.116 (130314) the "1" is the id of the sk data connection, the "116" is the N2K device src. If you scroll to the bottom of the Data Browser, you can dig down and find which device is "116".

[sbender9]

And BTW, if the temperature is coming from an Airmar DST800 or similar model (which Raymarine "rebrands"), the temp sensors are known to fail.

[wcbonner]

And BTW, if the temperature is coming from an Airmar DST800 or similar model (which Raymarine "rebrands"), the temp sensors are known to fail.

@sbender9 Thanks for the previous information on PGNs.

Yes my temperature reading is from the DST800 equivalent (Airmar Speed/Temperature Sensor 20-399-01) with the useless temperature. I've been thinking of getting a DST810 because it's supposedly more accurate on speed with a new paddlewheel, but it uses a different through hole size so isn't a project that can be done in the water.