Vaisala FD12P - Manual (Page 17)

Chapter 2 ___________________________________________________________Product Overview
VAISALA ________________________________________________________________________ 17
CHAPTER 2
PRODUCT OVERVIEW
This chapter introduces the FD12P Weather Sensor features,
advantages, and the product nomenclature.
Introduction
The FD12P Weather Sensor is an intelligent, multi-variable sensor for
automatic weather stations and airport weather observing systems.
The sensor combines the functions of a forward scatter visibility meter
and a present weather sensor. In addition, the sensor can measure the
intensity and amount of both liquid and solid precipitation.
The FD12P can be used to automatically determine the visibility and
precipitation related weather codes in the World Meteorological
Organization (WMO) standard SYNOP and METAR messages. The
sensor can also be employed as an observer's aid in a semi-automatic
weather observing system. The sensor is also suitable for other
weather observing systems providing valuable information, for
example, to road and harbor authorities.
The versatility of the FD12P is achieved with a unique operating
principle. The 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 data sufficient for an accurate
evaluation of current visibility and weather type.
Hardware Structure
The structural basis of the FD12P is the pole mast that supports the
transducer crossarm (FDC115). The crossarm contains the optical