Vaisala WS425 - Manual (Page 33)

Chapter 3 _______________________________________________________________ Installation
VAISALA _______________________________________________________________________ 33
Powering
Power Supplies
You can use any 12 VDC power supply with the unheated Ultrasonic
Wind Sensor, as long as it meets all applicable safety regulations.
Typically, the power supply is a fused 12 V battery with either a solar
panel charger or a trickle charger.
The power supply must be capable of delivering 155 mA current spikes.
The current draw of the Ultrasonic Wind Sensor alternates between
14 mA when idle, and short peaks of 155 mA during measurement
(typical). The average current consumption is 29 mA RMS.
NOTE Some DC power supplies are based on a chopper circuit that operates at
a 100 kHz frequency. Avoid using such power supplies with WS425
since the measurement can be distorted by the ripple in the DC output.
The heated ultrasonic wind sensors require +12 VDC for the sensor and
+36 VDC for the heater. The heating current is up to 0.7 A.
CAUTION The heated Ultrasonic Wind Sensor is intended for operation when pin
16 is connected to a +36 VDC source. If you are operating WS425 when
pin 16 is not connected to +36 VDC, you must ground pin 16. Never
float pin 16 on WS425 because the sensor will not report accurate
readings.