D-1
Appendix D. Wind Direction
Measurement Theory
It is not necessary to understand the concepts in this section for the general
operation of the 034B,
Wind Set
with a Campbell Scientific datalogger.
A 034B purchased from Campbell Scientific has a 9.53 k
Ω
fixed resistor and a
variable resistor on the excitation line. The variable resistor is adjusted by the
manufacturer so its resistance plus the 9.53 k
Ω
resistor equals the resistance of
the potentiometer (R
f
= R
s
+ R
t
).
FIGURE D-1. 034B potentiometer in a half bridge circuit
The vanes are calibrated due south and then the potentiometer is adjusted until
each half of the potentiometer has equal resistance.
