15
UT381/382 Instruction Manual
6. Illuminance measuring
● In process of measuring illuminance, the sensitive mirror must be
perpendicular to the measured illuminating source to ensure accuracy of
measured data..
● If distance between measured illuminating source and illuminometer,
positions or different of them, or the environment is different, then the
measured data will be different; cause, the intensity of light varies with
change of distance, position, angle and environment. Since the intensity
of light will be varied with its distance, position, angle and surroundings to
illuminometer, measured date will be different accordingly.
● Make sure there is no scratch or dirt on sensitive mirror of luminometer, or
the measured data won’t be accurate.
● When the illuminance exceeds the measuring range of the luminometer, “OL”
sign will be displayed.
● After completing measuring, cover the sensitive mirror with cap to avoid
scratch on sensitive mirror and keep it clean.
