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Operation
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4 Operation
4.1 Instructions for operating
4.1.1 Marking and aligning cuvettes
Even completely clean quality cuvettes exhibit tiny direction-
al differences in their light transmittance. Therefore, each
cuvette should be marked - both the measuring cuvettes as
well as the cuvettes with the calibration standards (refer to
section 2130 of the "Standard Methods for the Examination
of Water and Wastewater", 19th edition). Consequently,
each cuvette can always be inserted in the correct position
and you can achieve precise and reproducible measuring
results.
Clean the cuvette The cuvette must be absolutely clean (see section
5.2.2 C
LEANING THE CUVETTES
).
Marking a cuvette This is how to mark a cuvette (empty or full):
1 Switch on the turbidity measuring instrument by
pressing the key. Let the turbidity measuring in-
strument warm up for at least 75 s.
2 The cuvette must be closed with the black light pro-
tection cap. Make sure that the outside of the cuvette
is clean, dry, and free of fingerprints.
3 Insert the cuvette in the cuvette shaft.
4 Slowly rotate the cuvette by one complete rotation
(by 360 °) in small steps and hold the key de-
pressed while doing so. After each step, wait for a
moment until the display is stable. Watch the display
of the turbidimeter while you rotate the cuvette.
5 Turn the cuvette back to the position with the lowest
displayed value.