Expedition Navigation Software 
1 of 1- ZeeZee
- Expert
Offline - Registered: 3/30/2016
- Posts: 321
NMEA XDR sentences for Baro and Temperature not recognized
I've built a sensor device (Bosch BMP280 based) that outputs barometric pressure and temperature.
It's connected to my PC by USB and in Expedition I have configured the COM port as NMEA 0183 instrument type. This works perfectly for both Baro and Temp when I have the device sending the MMB and MTA sentences and have configured Exp to receive MTA and MMB. Here 2 examples of the data received in the 'raw data' window of Exp:
$WIMTA,19.95,C*2F
$WIMMB,29.407493,I,0.9958518,B*50
However, when I then configure the device and Exp to use XDR sentences for Baro and Temp (and have checked the corresponding XDR options), Exp does NOT display Baro and Temp although they are received in Exp. An example of the XDR sentences taken from the raw data window:
$WIXDR,C,19.95,C,BMP280*1F
$WIXDR,P,0.9958518,B,BMP280*08
Is my formatting of the sentence incorrect or is this a bug in Exp?
- Nick
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- Registered: 9/16/2015
- Posts: 2,964
Re: NMEA XDR sentences for Baro and Temperature not recognized
It is quite a flexible sentence and I just add types as they appear.
Exp currently recognises TempAir and AIRTEMP for air temperature and
BARO, BG or PRESSURE for barometer.
Here are a couple of existing samples
H5000:
$IIXDR,A,35.7,C,AIRTEMP,A,-1.-1,D,HEEL,A,1.4,D,TRIM,P,1.021,B,BARO,P,8.0,D,RUDDER*04
NKE
$IIXDR,P,1.02481,B,Barometer*0D
$IIXDR,C,19.52,C,TempAir*3D
- ZeeZee
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- Posts: 321
Re: NMEA XDR sentences for Baro and Temperature not recognized
As always, thanks again for the prompt and helpful response Nick!
I have implemented the NKE format and indeed now it works!
The 'transducer ID' in the sentence indeed needed to be changed to Barometer and TempAir.
I can still use talker ID $WI (it was not needed to be changed to $II as in the example). Likely it doesn't matter at all what talker ID is used.
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Thread Starter- Nick
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Re: NMEA XDR sentences for Baro and Temperature not recognized
You can just use baro or BARO as Exp just looks at the first 4 characters for that one.