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13.
Calibration
The sensor is shipped pre-calibrated, but since all electrodes are different, the sensor
must be calibrated with its electrode to give a good measurement. The electrode
degrades by time and calibrations shall be done regularly following a maintenance
schedule. The time between calibrations varies with the applications, it is usually
between one and ten weeks. It is important that the sensor has been switched on for
about 30 minutes prior to the calibration in order to stabilize.
Calibrating pH
For a pH calibration there are two alternatives: smart or manual. Irrespective of the type
of calibration you chose, you need two pH buffers which both have a common, known
temperature.
For a smart calibration you need two different buffer solutions with pH 4.00, 7.00, or
10.00.
For a manual calibration, two different buffer solutions can be used irrespective of the
buffer value.
Remove the sensor and, if necessary the electrode as well, but make sure that the
electrode is still connected to the signal amplifier. Make sure that you have at least 2
standard buffers available with pH 4.00, 7.00 or 10.00 of a known temperature (it is best
to pour the buffers into plastic cups).
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Enter the sensor menu. The output is frozen when the menu is opened.
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Open the “Calibrate” menu.
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Select "Calibrate", then "Smart" or ”Manual” and press ENTER.
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A window pops up and asks for the buffer temperature. Enter the temperature and
press ENTER
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BB2 will say ”Put the electrode in buffer 1”. Spray the electrode using clean water,
then immerse it in the first buffer, and press ENTER.
•
The text will say "Waiting for stable signal xxx,x mV", xxx,x is the millivolt signal
from the electrode. By pressing ENTER you can select to abort the calibration or to
accept the value shown.
•
If smart calibration is used and BB2 recognizes the buffer, BB2 will suggest a pH
value showing the text ”Accept smart calibration pH X.X”. You can choose to
accept the value or to change it manually.
•
If manual calibration is used BB2 will always ask for the value of the buffer, enter
the value and press ENTER.
•
BB2 will now tell you ”Put the electrode in buffer 2”. Spray the electrode using
clean water, then immerse it in the second buffer, and press ENTER.
•
The text will say "Waiting for stable signal xxx,x mV", xxx,x is the millivolt signal
from the electrode. By pressing ENTER you can select to abort the calibration or to
accept the value shown.
