User`s guide

Chapter 2 __________________________________________________________ Product Overview
VAISALA_______________________________________________________________________ 73
FD12 consists of a transmitter, a receiver, and a controller. The
simplified mechanical design means minimum disturbance to the
sample volume of air. The compact construction and factory set
mountings ensure easy installation and eliminate problems with startup
adjustments.
Present Weather Sensor
0305-047
Figure 68 Present Weather Sensor FD12P
Present Weather Sensor FD12P is an intelligent multi-variable sensor
that combines the functions of a forward scatter visibility sensor and a
present weather sensor. In addition, FD12P can measure the intensity
and amount of both liquid and solid precipitation.
The versatility of FD12P is achieved with a unique operating principle.
FD12P measures precipitation water content with a capacitive device
and combines this information with optical scatter and temperature
measurements. These three independent measurements together
provide sufficiently data for an accurate evaluation of prevailing
visibility and weather type.