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2.4 Message string WIMWV
WIND DIRECTION AND WIND SPEED
Example of data sequence with comma separated
fields: $WIMWV,357.0,R,5.2,M,A*CS<CR><LF>
field delimiter: , (comma)
header: $WIMWV
wind direction: 0.0 to 360.0
R: relative wind direction
wind speed: 0.4 to 60.0
M: metric units m/s
status A (valid) / V (not valid)
stop delimiters: <CR> <LF>
error code: WD 999.9
error code: WS 999.9
IMPORTANT! PLEASE NOTE:
FIELD LENGTH
The development of a NMEA decoder should not be proceeded from firm field lengths. The NMEA definition
proceeds from a variable field length. The comma character (“,”) serves as field disconnecting switch. Numeric values
in a field can be presented differently. In case a field is not sent, it has a length of 0 characters (,,) [comma-comma].
CHECK SUM
The check sum “CS” is covered to two ASCII characters hexadecimal value. “CS” calculated by XOR operation of each
character in the sentence between “$” and “*”, but excluding “$” and “*”.
ERROR CODE
In case, that the sensor cannot generate a measuring value because e.g. a sensor element is defect or implausible
(raw) values are collected the sensor outputs in the corresponding data protocol the above mentioned error code
(e.g. 999.9) and sets the status from “A” (valid) to “V” (not valid).
Example: $WIMWV,999.9,R,999.9,M,V*37<CR><LF>
PARTICULAR CHARACTERISTICS WIND DIRECTION VALUE
Theoretically the value for the wind direction can take any value between 0.0° and 360.0°. It should be noted, that
in a full circle the values “0.0” and “360.0” are describing the same direction. According to the international valid
recommendations of the WMO (World Meteorological Organization) in the “Guide to Meteorological Instruments
and Methods of Observation” (WMO-No.8) the wind direction value 0.0° just has to be output at calm. The sensor
follows the recommendation of the WMO and outputs at wind from the north the value “360.0” respectively “0.0” at
calm (lull).
NORMS
Emission
EN 60945:2002
CISPR 16-1 :1999 Part 1
Immunity
EN 60945:2002
includes:
EN 61000-4-6:1996
Injected RF currents
EN 61000-4-3:2002
Radiated RF fields
EN 61000-4-4:1995
Burst
EN 61000-4-2:1995
ESD
EN 61000-4-5:1995
Surge
EN 61000-4-11:1994
Voltage variations
