Vaisala FS11 Technical data

P.O. Box 26, FI-00421 Helsinki, FINLAND

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www.vaisala.com

Vaisala FS11 Visibility Sensor for RVR Applications

Features/Benefits

• Especially built for Runway
Visual Range (RVR) Applications

• Meets FAA and ICAO
specifications for visibility
measurement

• Selected by FAA

• Accurate and traceable
measurement

• Mechanical design and high­power heating follow FAA
guidelines

• Range up to 75 km

• Can also be used for
aeronautical and SYNOP
visibility measurements

• Composite fiber mast meets
the frangibility requirements of
airports

Scientifically valid chain of
calibration

Every Vaisala FS11 is calibrated
through a scientifically valid chain of
reference. e scattering response of the
calibration device can be clearly traced
to a reference FS11 visibility sensor,
which is in continuous operation at
Vaisala outdoor test field along with
reference transmissometers and other
instrumentation.

Low maintenance need

e FS11 incorporates a new technique
that measures and compensates for
window contamination. It ensures
unparalleled measurement accuracy
throughout the interval between
window cleanings. It also enables much
longer window cleaning intervals than
the former RVR visibility sensors. e
unique system works by monitoring the
total reflectance of the window surface.
It automatically compensates for

visibility measurement errors caused by
window contamination.

e sophisticated self-diagnostics and
modular design allow for very short
service times. e measurement fork
and optional background luminance
meter (LM21) are independent
instruments that can be replaced
quickly as pre-calibrated spare parts.

Reliable operation in the
harshest weather

Four main design features are combined
in the FS11 to ensure reliable operation
in the harshest weather. e first is the
window contamination compensation
technique. e second is the "head­down" design of the optical heads,
which protects them against virtually all
windblown particles (even those flying
horizontally).

High-power heaters are the third
feature, each with its own temperature
monitoring and control mechanism to
prevent snow accumulation during the
heaviest snowstorm.

As a final measure, there is an optical
path clearance monitoring circuitry to
verify that measurement is not affected
by obstructions.

FS11

Technical Data

VISIBILITY

Operational

Measurement range
(MOR)
Accuracy ± 10 % range 5 m ... 10,000 m

Scatter measurement
accuracy

5 m ...75,000 m; 1, 3 and 10 min

averaging

± 20 % range 10,000 m ... 75,000 m

±3 %

Optical

Operating principle Forward scatter measurement
Scattering angle 42°
Light source Near infrared Light Emitting Diode

Electrical

Mains supply 100/115/230 VAC ±10 %, 50-60 Hz
Power consumption 300 VA maximum

Outputs Serial line RS-232 or opto-isolated

(60 VA + 240 VA desfrosting heaters)

RS-485 (2-wire) or optional data

modem

Separate RS-232 maintenance line

Mechanical

Dimensions 2.8 m x 0.9 m x 0.5 m
Weight 37 kg
Mast Frangible and hinged composite-fiber mast

Electromagnetic compatibility

CE compliant

Compliance has been verified according tot he following

EMC directives:

Verification subject Standard

Radiated emissions EN55022
Radiated susceptibility IEC 1000-4-3, 10 V/m
Conducted emissions EN55022
Conducted susceptibility IEC 1000-4-6
IFT immunity IEC 1000-4-4
ESD immunity IEC 1000-4-2
Surge IEC 1000-4-5
Harmonics to the mains
network

IEC 1000-3-2

Accessories/Options

Calibration set FSA11
Background luminance sensor LM21
Battery backup FSB101

typical backup time 30 min at 25 °C
Modem for long distance (> 1km)
communication
Obstruction light FS110BS

DMX501

Environmental

Operating
temperature
Operating humidity 0 ... 100 %
Wind speed Up to 60 m/s

-40 ... +65 °C, optional -55 ... +65 °C

Specifications subject to change without prior notice.
© Vaisala Oyj

Ref. B210244EN-B 2006-12