Chapter 2 __________________________________________________________ Product Overview
VAISALA _______________________________________________________________________ 23
CHAPTER 2
PRODUCT OVERVIEW
This chapter introduces the features, advantages, and the product
nomenclature.
Description and Purpose
Vaisala Transmissometer LT31 requires a 115/230 VAC power supply
and an RS-232 or RS-485 cable, or a single pair modem line for
communication. LT31 sends visibility and status messages to a remote
display unit or data processing system.
A set of built-in commands and test routines are provided for the
configuration and monitoring of the multiple LT31 functions. During
assembly and maintenance, a laptop with a VT100 emulation terminal
program is needed for checking the system parameters and changing their
values.
LT31 Key Features
The key features of LT31 are listed in this section.
Range Extension
The signal conditioning and A/D converter technology specific to
Transmissometer LT31 allows coverage for the whole runway visual
range (RVR), as well the range required for aeronautical visibility with a
single baseline system.
Auto-calibration
A forward scatter sensor is an integral part of the LT31 system. It is used
to fully calibrate the transmittance measurement automatically. This
allows compensation for window contamination and misalignment in the
medium and long term.