User manual

1-Wire Application Guide v1.04 Page 20 of 41
are known and wind direction is now absolute. There are two conditions when
West might become East, and vice versa; if you install the PCB upside down
(easy to do!) and when you would rather know where the wind is blowing from
rather than blowing to. TEMP08 offers the REV command to flip East and West,
and all the other cardinal points, to do this.
There are now new wind direction sensors on the market that use DS2438’s to
determine direction. These are not directly compatible with TEMP08 wind
conversions, however, can still be used if the DS2438 type is set to “V” (voltage).
Translation of the voltage to wind direction will need to be done by the PC
connected to TEMP08. Hobby Board sells both the Inspeed and ADS wind
direction sensors based on DS2438’s.
To calculate the wind direction for the Inspeed sensor use the following formula:
D = 400 x (V
AD
– 0.05 x V
DD
)
V
DD
Where:
D=wind direction in degrees
V
AD
=wind vane output voltage
V
DD
=supply voltage
To calculate the wind direction for the ADS sensor use the following Table(s):
Table 2 ADS Wind Direction Conversion
Direction Voltage
N 2.66-2.72
NNE 6.49-6.55
NE 5.96-6.02
ENE 9.35-9.41
E 9.27-9.33
ESE 9.50-9.56
SE 8.48-8.54
SSE 8.98-9.04
S 7.57-7.63
SSW 7.95-8.01
SW 4.28-4.34
WSW 4.59-4.65
W 0.89-0.95
WNW 2.20-2.26
NW 1.54-1.60
NNW 3.54-3.60