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.

   

My setup: the baro data comes from enviro pHAT attached to the 40 pins of raspberry pi 4. The baro data 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.

     

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):

Code:

<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>

Is it because a comma is missing in the NMEA sentence. For example, in

Barometer*17<0x0D><0x0A>

between 'Barometer' and the checksum '17<0x0D><0x0A>'? Therefore, the format is not valid? 

Any ideas how to debug this? Many thanks!

[PaddyB]

Is it because a comma is missing in the NMEA sentence. For example, in

Barometer*17<0x0D><0x0A>

between 'Barometer' and the checksum '17<0x0D><0x0A>'? Therefore, the format is not valid? 

Any ideas how to debug this? Many thanks!

Sentence looks OK in nmea checksum calculator
https://nmeachecksum.eqth.net/
Command:$*
With checksum:$IIXDR,P,1.0155,B,Barometer*17

Mine is the same, assumming it's because signalk creates a XDR nmea0183 sentence, not a MDA sentence, which is obsolete apparently >>
https://opencpn.org/wiki/dokuwiki/doku.p..._sentences
"MDA
Meteorological Composite (obsolete) This message is obsolete and NMEA recommends to use XDR transducer messages instead. However, old instruments might still sending this message."

Maybe more of an Opencpn question than openplotter.
https://www.cruisersforum.com/forums/f134/

Or probably possible to do a hack in node-red. 

[volksbar]

Is it because a comma is missing in the NMEA sentence. For example, in

Barometer*17<0x0D><0x0A>

between 'Barometer' and the checksum '17<0x0D><0x0A>'? Therefore, the format is not valid? 

Any ideas how to debug this? Many thanks!

Sentence looks OK in nmea checksum calculator
https://nmeachecksum.eqth.net/
Command:$*
With checksum:$IIXDR,P,1.0155,B,Barometer*17

Mine is the same, assumming it's because signalk creates a XDR nmea0183 sentence, not a MDA sentence, which is obsolete apparently >>
https://opencpn.org/wiki/dokuwiki/doku.p..._sentences
"MDA
Meteorological Composite (obsolete) This message is obsolete and NMEA recommends to use XDR transducer messages instead. However, old instruments might still sending this message."

Maybe more of an Opencpn question than openplotter.
https://www.cruisersforum.com/forums/f134/

Or probably possible to do a hack in node-red. 

Thanks for the confirmation. I re-posted in opencpn forum in case anyone knows a quick fix. (I don't know at this stage how to hack the node-red...)