Hach-Lange POLYMETRON 9245 User Manual - Manual (Page 90)

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Calibration
8.4.2 One point calibration
When the measurement is stable, the details are displayed at
the top of the screen against measurement P1.
The overflow vessel is then rinsed and re-filled with sample
plus 20mL of the calibration solution.
This sample is then measured and the details displayed
against P2.
Once the final measurement is stable, the offset and slope for
this calibration are calculated.
The default values of the offset and slope are displayed along
with the calculated values for the last and current calibration.
A message is displayed indicating the success or failure of the
calibration.
For the details on how this success or failure condition is
determined, and how to proceed, see the description in
Calibration results on page 91 .
Select the MAN.OFFSET CAL option to start the one point
calibration process.
This process requires that a calibration solution of known
sodium concentration is available.
Refer to Calibration solution concentrations on page 85 for
information regarding the concentration of the calibration
solution.
If necessary, enter the concentration of the calibration
solution, and select START to initiate the calibration process.
Then, provided the reactivation frequency parameter is not
zero (as is highly recommended), the electrode is reactivated.
On completion this is followed by a rinsing of the overflow
vessel.