Vaisala WAT12 - Manual (Page 21)

Chapter 3 __________________________________________________ Installation
VAISALA__________________________________________________________19
The following numbers refer to Figure 10 on page 18.
1 = Anemometer cable
2 = Glands for power and signal cables
3 = Wind vane cable
Signal Output
The signal output provides two analog current loops,
direction and speed, with sourcing drivers with an o/p
driving voltage 10.5 V typically and an o/p resistance of
57
Ω . The loops return to the common ground for power
and signal. The signal and sensor power outputs are also
current limited.
Typically, only a 4-wire shielded cable is required for the
line between the WAT12 transmitter and the receiving end.
Two of the four wires provide the operating power for the
system. The other two are for the current source outputs
from the WAT12 transmitter; one delivering the speed
signal and the other the direction signal. The two readout
devices are wired each across the respective current source
terminal (+) and the negative terminal of the power supply
(-). Refer to Figure 11 below for a typical system with a
24 VDC power supply and the 5 mA signal currents.
0206-049
Figure 11 Typical System with 24 VDC Power Supply
and 5 mA Signal Currents