Plots plugin - barometer error: nan

[volksbar]

Hello,

I would like to track baro changes using the 'Plots' plugin but got 'nan' and no baro data when plotting. (see attached pic 1)

My setup: the baro data comes from enviro pHAT attached to the 40 pins of raspberry pi 4. The baro sensor detected on the i2c app and the signalk connection was established. I can see the pressure and temp data on signalk without problems. The pressure is also correctly displayed on opencpn's dashboard.

(see attached pic 2)

Since 'Plots' plugin for barometer expects NMEA/ MDA, the baro data on signalk is then converted to NMEA0138.

Here is the problem:
The 'Plots' plugin shows only nan and no data goes into it. From the NMEA debug window, I got the following (red indicates error):

<GREEN>18:50:52 (TCP:localhost:10110) $IIXDR,P,1.0155,B,Barometer*17<0x0D><0x0A>
<RED>--> 18:50:52 (TCP:192.168.14.1:20220) $IIXDR,P,1.0155,B,Barometer*17<0x0D><0x0A>
<GREEN>18:50:53 (TCP:localhost:10110) $IIMMB,29.9900,I,1.0156,B*71<0x0D><0x0A>
<RED>--> 18:50:53 (TCP:192.168.14.1:20220) $IIMMB,29.9900,I,1.0156,B*71<0x0D><0x0A>
<GREEN>18:50:53 (TCP:localhost:10110) $IIXDR,P,1.0156,B,Barometer*14<0x0D><0x0A>
<RED>--> 18:50:53 (TCP:192.168.14.1:20220) $IIXDR,P,1.0156,B,Barometer*14<0x0D><0x0A>

Any ideas how to debug this? Many thanks!

[rgleason]

What the dickens? Are you trying to use Plots_pi to show barometer data?
That is not its purpose. Please read the manual. Thanks.


LATER: Actually that looks like Dashboard_pi which does have an instrument for barometer.

It looks like you've got the barometer data, but are the checksum ok?
Try verifying the checksum for starts.

[volksbar]

@rgleason:

I would like to track baro changes over time, as clearly indicated in my previous post! Dashboard shows the baro at the current point but does not track it!

As for the checksum, the format is correct and the value is fine (according to http://www.hhhh.org/wiml/proj/nmeaxor.html).

[nohal]

The Dashboard has an instrument named Barometric history, which shows the pressure changes over time.
If you have Signal K data available, the DashboardSK plugin can draw history of absolutely anything.

[barcoMeCasa]

Originally Posted by rgleason

What the dickens? Are you trying to use Plots_pi to show barometer data?
That is not its purpose. Please read the manual. Thanks.


LATER: Actually that looks like Dashboard_pi which does have an instrument for barometer.

It looks like you've got the barometer data, but are the checksum ok?
Try verifying the checksum for starts.

It's the plots plugin. As well as speed/winf it can graph barometer data



But the pressure data input needs to be MDA, not XDR.

[rgleason]

@barcoMeCasa Bravo! I just learned something. Sorry for the mis-information.

It's the plots_pi plugin. As well as speed/winf it can graph barometer data
But the pressure data input needs to be MDA, not XDR.

You found another little gift from Sean! I have been wanting to implement this graph of information somehow into the barometric plugins. NmeaConverter willl convert XDR to MDA. But maybe we should update this....to accept XDR which is more standard now.

https://opencpn-manuals.github.io/main/plots/index.html
https://opencpn-manuals.github.io/ma...ter/index.html

David Burch advises
We have a new high-accuracy, low-cost barometer that works great in OpenCPN. This video shows how to set it up: https://youtu.be/ZqQN4uWb9hI


Also I think this Barometer Cheat Sheet Information should be a part of the plugin somehow.


https://sailingeurybia.com/reading-b...m-cheat-sheet/
https://www.sailingeurybia.com/wp-co...r-WBF-2016.pdf

[volksbar]

Originally Posted by rgleason

@barcoMeCasa Bravo! I just learned something. Sorry for the mis-information.



You found another little gift from Sean! I have been wanting to implement this graph of information somehow into the barometric plugins. NmeaConverter willl convert XDR to MDA. But maybe we should update this....to accept XDR which is more standard now.

https://opencpn-manuals.github.io/main/plots/index.html
https://opencpn-manuals.github.io/ma...ter/index.html

David Burch advises
We have a new high-accuracy, low-cost barometer that works great in OpenCPN. This video shows how to set it up: https://youtu.be/ZqQN4uWb9hI


Also I think this Barometer Cheat Sheet Information should be a part of the plugin somehow.


https://sailingeurybia.com/reading-b...m-cheat-sheet/
https://www.sailingeurybia.com/wp-co...r-WBF-2016.pdf

Many thanks! NmeaConverter_pi solved it!

I converted XDR to MDA so that the Plots_pi can get the data input.

$IIMDA,,,$IIXDR2,$IIXDR3,,,,,,,,,,,,,,,,

It would be great if Plots_pi can accept XDR instead of the obsolete MDA.

[Corsair63]

Originally Posted by volksbar

Many thanks! NmeaConverter_pi solved it!

I converted XDR to MDA so that the Plots_pi can get the data input.


It would be great if Plots_pi can accept XDR instead of the obsolete MDA.

it is very curious because I had same problem with pressure sensor in my computers.

I have one USB sensor for computers that transmit XDR & MDA & MTA so there is no problem at all with Dashboard data.

also, I have the mobile with "BT GPS" app that send he pressure data with only XDR sentence.
disconnected the USB sensor and connected mobile via BT and dashboard in the windows computers (O 5.9.0) doesn't show the pressure reading in the dashboard. but the value is shown in the dashboard of the RPi4 under O 5.8.4-3, and it's transmitting only XDR sentence.

just in case I need that data for the tablet, and I did a conversion with NMEAConverter app and now shown.

are the same version of Dashboard app different for different o.s.?

[rgleason]

are the same version of Dashboard app different for different o.s.?

No, I don't believe the base code is that different, but depending on the OS and the external build libraries being used, it can be different functionally, ie Windows libs, Linux libs, Flatpak libs, MacOS libs, Android Libs. There is a common set of opencpn-libs which helps. That is a complicated answer, so yes they are different but not necessarily in the way that you meant?

[Corsair63]

Originally Posted by rgleason

are the same version of Dashboard app different for different o.s.?

No, I don't believe the base code is that different, but depending on the OS and the external build libraries being used, it can be different functionally, ie Windows libs, Linux libs, Flatpak libs, MacOS libs, Android Libs. There is a common set of opencpn-libs which helps. That is a complicated answer, so yes they are different but not necessarily in the way that you meant?

my computers are as follows:

Windows 11 (x64)
OCPN Version 5.9.0-0+d40a564 Build 2024-02-25
Dashboard Version: included in OCPN build

Raspi 4 - 8 GB
Debian (Bookworm) x64
OCPN Version 5.8.4 Build 2023-07-21
Dashboard Version:  included in OCPN build

and really happens what I talking, in windows version XDR pressure is not shown in the dashboar but it's shown the same XDR in Raspi version.

[rgleason]

I wrote @Hakan about it he may have an explanation.

[Hakan]

corsair..
In 5.9 the XDR barometer pressure was "narrowed" to exclude other pressures like oil pressure.
To be recognized as an outside air pressure the VDR shall include:
TransducerType == "P", UnitOfMeasurement == "B" and (and this is new) TransducerName.MakeUpper() .Contains "BARO" That is any upper/lower of the letters "baro".
That was the change, correct or not.
I suppose your XDR sentence don't include the text "baro" in the name part (#4) of the quadruple?

[Corsair63]

just an example of date received.

in windows, also, notice that in WD plugin XDR data are not shown too.

[Hakan]

Corsair..
I played the data from your picture.
Shows fine in Dashboard OCPN 5.9 current Github master:

[Corsair63]

Originally Posted by Hakan

Corsair..
I played the data from your picture.
Shows fine in Dashboard OCPN 5.9 current Github master:

I'll update to latest 5.9.0. and revert with findings.