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5 Calibration
In order to perform accurate pH measurement with a Sentron SI meter, it must be calibrated before
use. Generally, a calibration should be performed each time the meter is switched on or when a
different probe is attached. In practice this means calibration should be performed at least daily.
The calibration process consists of placing a probe attached to the Sentron pH meter in one, or a series
of, buffer solutions with a predetermined pH. The type of calibration, and the number of calibration
points depend on several factors. In general, the more buffers that are used, the more accurate the
calibration will be. A detailed explanation of the calibration process, and the considerations for
choosing the number of calibration points, can be found in section 5.1.
The Sentron SI meter displays a calibration results at the end of each calibration and stores the
calibration results in a report. This report is available for review at a later time. Please review section
5.4 for detailed information on accessing and interpreting calibration reports.
The Sentron SI meter can provide a warning as a reminder to perform a calibration. The warning will
be activated after a user definable time period since the last calibration. It is recommended to set this
calibration reminder time at an appropriate setting for the intended application. This function is
explained in section 5.5
The Sentron SI 400 meter can only be calibrated using Sentron buffer sets. The SI 600 meter can be
calibrated using Sentron, DIN, NIST and JIS buffer sets. The process for changing the buffer set
configuration is explained in section 5.6 below.
