Unitest 93408 Bedienungsanleitung Seite 19

Measurements in compliance with DIN 5035, section 6
• For more accurate measurements (e.g for distribution curves), measure and monitor the
lamp voltage supply since voltage fluctuations result in incorrect data. When measuring tu-
bular fluorescent lamps, also measure ambient temperature since the luminous flux of such
lamps is greatly influenced by temperature.
• Switch on the instrument by pressing button "POWER".
• Switch off the instrument by pressing button "POWER".
• Ensure that the HOLD function (data hold) is switched off.
• Always choose the highest measurement range using the "RANGE" button. If necessary, it
is then possible to switch to smaller ranges. Please note that long-term measurement ac-
curacy is adversely affected when overloading the sensor for a long time period if the illu-
mination intensity is too high for the selected range.
• Only remove the sensor cover shortly before measurement and replace immediately after
measurement.
• If the symbol for range overload (figure "1" appears in display) is displayed, select the next
largest measurement range by pressing "RANGE" button.
• A displayed value is stored when pressing the "HOLD" button.
• When measuring horizontal illumination, hold the sensor horizontally in front of the object
to be measured so that the diffuser window of the sensor cell faces the ceiling. The distance
between floor and cell is 0.85 m for routine room measurements and 0.2 m for indoor traf-
fic measurements.
• During measurement, the height of the measurement point and the sensor position have
to meet the requirements.
• Shadows and reflections of objects and bodies can result in measuring errors. These er-
rors can be minimised by holding the sensor at a sufficient distance from the body and in
a horizontal position.
• Due to the influence of lighting intensity and operation time on the sensor, a regular instru-
ment calibration is recommended to obtain constant measurement precision.
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