Calibrating Conductivity; Using An External Chart Recorder - GE pH/C-900 Operating Instructions Manual

5 Operation
5.6 Calibrating pH and conductivity
5.6.1 Calibrating pH
Calibrating with the electrode in
the flow cell
When calibrating with the electrode fitted in the flow cell in ÄKTApurifier, follow the above
procedure. Before adjusting the pH monitor, ensure that the pH has stabilized. Leave
the pump running while calibrating. Switch to the other standard buffer solution and
repeat the procedure. For a description of calibration from UNICORN with the electrode
fitted in the flow cell, see section 6.6 in UNICORN User Manual.
5.6.2

Calibrating conductivity

The cell constant for the particular flow cell is written on the flow cell packaging. Refer
to Entering the conductivity cell constant, on page 43 for how to enter the cell constant.
Adjustment of the cell constant is only necessary when the monitor is to be used to de-
termine specific conductivity with high accuracy. The procedure is described in Calibrating
the conductivity cell, on page 41. Calibration can also be performed from UNICORN.
5.7

Using an external chart recorder

The external chart recorder outputs for pH and conductivity from the monitor are 0 V to
1 V. There is also a 4 mA to 20 mA signal available at the same output connectors.
For the conductivity signal, 0% represents 0 V and 100% represents 1 V as set under
main menus Set Cond scale 0% and Set Cond scale 100%.
For the pH signal, the full scale and zero level has to be set according to below.
Step
1
2
3
4
52
Action
Select main menu Set pH Analogue Out, press OK.
Select sub menu Set pH Full Scale. Set the range
value, press OK. The range is the full scale pH range
for the chart recorder (1 V).
Select sub menu Set pH Zero Level, press OK.
Set the value, press OK. The zero level is the pH value
corresponding to 0 V to the chart recorder. The differ-
ence between zero level and full scale must be at
least 1 pH unit.
Display
Set pH Analogue Out
Set pH Full Scale
(pH12.00)
Set pH Zero Level
(pH 2.00)
Monitor pH/C-900 Operating Instructions 29-0549-25 AB
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