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10. Taking measurements
In order to obtain precise measured values, the measuring instrument must be adjusted to the
ambient temperature. Allow the device to adjust to the ambient temperature after relocation.
Lengthy UV measurements on light sources with high temperatures can cause self-heating of the
meter and thus a faulty measurement if the measuring distance is small. In order to obtain precise
measured values, remember the following rule of thumb: The higher the temperature, the greater
the measuring distance and the shorter the measuring time.
a) Performing the UV measurement
To perform the UV measurement, proceed as follows:
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Put the meter into operation. After turning on, the meter is always in the large measurement range of 20 mW/cm².
This range is intended for measurements from 2 to 20 mW/cm².
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Remove the sensor protective cap from the sensor.
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Align the sensor surface as perpendicular as possible to the light source.
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The measured value appears on the display.
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Change the measurement range to perform measurements less than 2 mW/cm². To do this, press the button with
the inscription “2” (5). To switch the measurement range, press the respective range button “2” (5) or “20” (6).
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If “- - - -” appears on the display, the measurement range has been exceeded. Switch to a larger measurement
range if possible.
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Turn off the meter when the measurement is completed. Replace the sensor protective cap.
b) Zero adjustment
To achieve high accuracy, the meter can perform zero adjustment. Zero adjustment is only possible and useful if the
display shows a measured value of ≤0.1 mW/cm².
To perform zero adjustment, proceed as follows:
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Cover the sensor head with the lightproof sensor cover (17).
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Press and hold down the “2 mW/cm²” range button (5) for approx. 2 seconds. Zero adjustment is signalled with a
beep. The measured value on the display is reset to zero.
c) Holding the measured value (“HOLD”)
The current measured value can be held to obtain a longer reading time. To hold the measured value, press the
“HOLD” button.
The keystroke is signalled with a beep. The measured value and the “HOLD” symbol appear on the display.
To disable the function, press the “HOLD” button again. “HOLD” disappears from the display.
