YSI IQ S ENSOR N ET VARiON Plus 700 IQ - Manual (Page 32)

Matrix adjustment, check and calibration VARiON
®Plus
700 IQ
4 - 2 ba76000e01 01/2012
Drift potential Simultaneously with the matrix adjustment (or calibration), the drift
voltage DV(mV) of the combination electrode is determined. It serves
to evaluate the long-term behavior of the combination electrode. The
drift voltage changes due to the following factors:
 Influences due to the sample composition (matrix)
 Changes of the electrode characteristics.
Electrode zeroing The temporal change of the drift voltage is recorded in the calibration
history so the long-term behavior of a combination electrode can be
evaluated. As a start value, the user has to set the drift voltage to zero
at the beginning of this evaluation period in order to observe changes
in the calibration history.
The electrode zeroing itself is carried out with the matrix adjustment (or
calibration) procedure for the selected combination electrode(s). It
becomes effective if the procedure was successfully carried out.
For each electrode, the user can carry out the electrode zeroing
separately and at any time. We recommend, however, to start the
evaluation period with the commissioning of a new or different
electrode to be able to see the entire operating life of an electrode in
the calibration history.
It is not possible to zero an electrode with the Check procedure, as this
procedure stores no data in the sensor.
Resetting the slope by
electrode zeroing
Electrode zeroing with the matrix adjustment procedure resets the
slope to the default setting (+ or - 59.2 mV) at the same time. Electrode
zeroing with the calibration procedure replaces the existing slope with
the newly determined value.
Maintenance and
calibration case,
VARiON
®
Case
For adjustment, calibration and maintenance activities on site, the
VARiON
®
Case is available. The convenient case provides room for all
required accessories (details, see section 6.1).