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21. Selecting Buffers for Auto Buffer Recognition
The
hydro
CHEM
is factory set to automatically recognise pH4.00, pH6.88 and pH9.23 buffers.
However, some users may prefer to use pH7.00 instead of pH6.88 and pH10.06 instead of pH9.23.
The following procedure describes how to set which of these buffers are automatically recognised at
calibration.
1. Select the Setup menu (
→
→
F5:System
→
→
F5:Setup
).
2. Select
F4:Buffer
from the menu. The
hydro
CHEM
now prompts you to select the Primary
Buffer you wish to use for calibration…
Select Primary Buffer
→
→
F1:6.88pH F2:7.00pH
The arrow indicates the current selection.
Press
to select pH6.88 as the primary buffer.
Press
to select pH7.00 as the primary buffer.
Press
to quit and retain the current buffer settings.
3. If
or
was press above, the
hydro
CHEM
will now prompt you to select the Secondary
pH Buffers you wish to use for calibration…
Select Secondary Buffers
→
→
F1:4.00/9.22pH F2:4.00/10.06pH
The arrow indicates the current selection.
Press
to select pH4.00 and pH9.23 as the secondary buffers.
Press
to select pH4.00 and pH10.06 as the secondary buffers.
Press
to quit and retain the current buffer settings.
Note:
pH6.88 buffer is a DIN 19266 and NBS Primary-standard pH solution. Its use is highly
recommended for the most accurate possible results. If pH7.00 buffer is used, ensure that it
is manufactured to 0.01pH accuracy. pH7.00 buffer has a buffer capacity less than half that
of pH6.88 buffer and is therefore much less stable.
