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!