WMT700 NMEA MWV data message is as follows:
$<id>MWV,<dir>,<ref>,<spd>,<uni>,<sta>*<chk><CR><LF>| Name | Description |
|---|---|
| $ | Message header |
| <id> | Two character sensor ID; AA … ZZ |
| MWV | Fixed text |
| <dir> | Wind angle: 0 to 359° |
| <ref> | Reference: R = relative |
| <spd> | Wind speed |
| <uni> | Wind speed unit: K = km/h M = m/s N = knots |
| <sta> | Status: A = Valid data V = Invalid data |
| * | Fixed text |
| <chk> | Checksum (8-bit XOR, excluding $ and *) |
| <CR> | Carriage return code, ASCII 0DH |
| <LF> | Line feed code, ASCII 0AH |
Example of the command and response:
$IIWIQ,MWV*2F<CR><LF>
$WIMWV,045,R,011.63,N,A*09<CR><LF>Interpretation of the example message:
- Talker ID "II" queries the WMT700 NMEA MWV message from sensor which has address parameter set to "WI".
- WMT700 responds with talker ID "WI" and the requested MWV message. The reported relative wind direction is 045 degrees and the wind speed is 11.63 knots.
Missing readings
If data is missing due to a measurement problem, the NMEA messages show V in the status field. Wind speed and wind direction fields are left empty.