Introduction - Omega HHLM112SD User Manual

INTRODUCTION

Thank you for purchasing the HHLM112SD UV Light Meter with Data Logging SD card.
Please read this user's manual carefully and thoroughly before using the instrument.
The HHLM112SD is a general-purpose handheld instrument suitable for measuring
the intensity of light in commercial, industrial and consumer settings. Applications
include photography, videography, construction, engineering and surveillance.
This light meter measures light intensity using either of two units: lux or foot-candles.
The lux is the standard international unit of illuminance, or how much luminous flux
is spread over a given area. One can think of luminous flux as a measure of the total
"amount" of visible light present, and illuminance as a measure of the intensity of
illumination on a surface. A given amount of light will illuminate a surface more dimly
if it is spread over a larger area, so illuminance is inversely proportional to area.
The standard international unit of luminous flux is the lumen, and one lux is equal to
one lumen/m2. For perspective on lux readings from the natural world, consider that
a moonless clear night sky has an illuminance of about 0.002 lux, while direct
sunlight has an illuminance of 30,000 to 130,000 lux.
The footcandle (or lumen per square foot) is a non-standard unit of illuminance.
Like the Btu, it is mainly in common use only in the U.S., particularly in construction-
related engineering and in building codes. Because lux and footcandles are different
units of the same quantity, it is perfectly valid to convert footcandles to lux and vice
versa. One footcandle (ft-cd) = 10.764 lux.
The HHLM112SD has the performance and features needed to satisfy the most
demanding aspects of the above applications. It also has the ability to measure
surface temperature, using an optional Type K of Type thermocouple. A light probe
comes standard with the instrument.
Because it is microprocessor-based, the HHLM112SD can make full use of the
portability, reliability and large storage capacities that SD memory cards offer.
Measurements of light intensity or temperature can be made automatically at any
of 11 sampling rates between one second and one hour. After time-stamping and
storing the measurements on an SD card plugged into the instrument (a process
called datalogging), the user can remove the card and transfer the measurements
to a laptop or desktop computer either directly or via a USB card reader.
The HHLM112SD has a backlit 2-1/2 in. diagonal display and is powered by six "AA"
Alkaline batteries or an optional 9-VDC AC adapter.
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