Zero Adjustment - wtw photolab S12 Operating Instructions Manual

11. Zero adjustment

Zero adjustment is necessary
after changing the lamp
after the error message, PhotoCheck (AQA1)
occurs
on initial commissioning
if the photometer was mechanically stressed, e.g.
percussion, transport
if the ambient temperature changed by more than
5 °C since the last zero adjustment
at least every six months.
When performing the zero adjustment with a round
cell observe the following points:
Only use a clean, scratch-free round cell with
distilled water. A prepared zero cell is provided with
your photometer. In addition, a prepared zero cell
is contained in the scope of delivery of the Photo-
Check (article 14693).
If the round cell is visibly contaminated, or at least
every 24 months, clean and refill it (minimum filling
level 20 mm). Then check the cell for scratches.
When performing the zero adjustment with a rectan-
gular cell observe the following points:
With rectangular cells, the adjustment must be
made using the same cell type (manufacturer) as
for the measurement. This is important because
glass of different manufacturers has different
absorption behavior. When changing the cell type
always repeat the zero adjustment with the new
type.
Clean the rectangular cell before performing the
zero adjustment and fill it with distilled water
(minimum filling level 20 mm).
For measurement, always insert rectangular cells
in the cell shaft with the same orientation as during
the zero adjustment (e.g. cell labeling always on
the left side).
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