Xylem IQ SensorNet ViSolid 700 IQ (SW) - Manual (Page 30)

Measuring ViSolid
®
700 IQ (SW)
4 - 2 ba76040e02 07/2013
4.2 Calibration for TSS measurement
4.2.1 General information
Why calibrate? The following factors can change with time and affect the measurement
results:
 the optical characteristics, e.g. color and particle size, and the
density of the measuring medium (e.g. dependent on the season)
 the conditions at the measuring location (e.g. due to growing
deposits on the ground and walls)
The effect of the measurement environment can be reduced by
ensuring the optimum conditions (see section 3.3.1) and can be
compensated by a user calibration (see section 4.2.4).
When to calibrate? A new calibration is required if there is any change of the
characteristics of the measuring medium or any change of the
environment at the measuring location.
Note
Calibration data that are entered are stored in the controller and, thus,
assigned to the measuring location (and not the sensor). Thus, if the
sensor is replaced, no new calibration is required.
How is a calibration
carried out?
The actual level of total suspended solids of your measuring medium is
determined by a reference measurement (e.g. gravimetric according to
DIN 38414).
If the reference measurements do not deviate from the optically
determined level of total dissolved solids of the ViSolid
®
700 IQ (SW),
the sensor is already optimally adapted to the measuring situation.
If the reference measurements deviate from the optically determined
level of total dissolved solids of the ViSolid
®
700 IQ (SW), a calibration
is required.
The following calibration options are available:
 Calibration by adapting the Correction factor setting
if the values displayed with Default calibration deviate from the
actual values by a specific factor
 Performance of a User calibration
if the values displayed with Default calibration and Correction factor
no longer agree with the actual values