YSI IQ SensorNet ViSolid Sensor 700 IQ - Manual (Page 36)

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Measuring ViSolid
®
700 IQ (SW)
Procedure of the
calibration
A measurement of the total suspended solids will deliver
ever more accurate measurement results the closer the
composition of the measuring medium corresponds to the
status at the time of the calibration. If there is a fundamental
change of the characteristics of the sample, a new calibra-
tion may be necessary.
1 Bring the sensor into the measuring position.
2 In the setting table of the TSS sensor, select the
mg/l TSS measuring mode and the AutoRange measuring
range (see section 3.5.3).
3 Switch to the measured value display with <M>.
4 When the measured value is stable, read the SiO2 value
(marked with "#"), convert it into the unit (mg/l) if necessary,
and note it down.
5 Take a sample as close to the same time as the SiO2 mea-
surement as possible and as close to the sensor as possible.
6 Determine the level of total suspended solids of the sample
according to a reference procedure (e.g. gravimetric according
to DIN 38414) and note it down together with the measured
value of SiO2 as the TSS/SiO2 value pair in mg/l.
At least one value pair and a maximum of eight value pairs
can be entered for a valid calibration. Keeping to the
descending order of values is very important. Not keeping
to the order will result in a calibration error.
7 For a multi-point calibration:
Repeat the determination of the value pair for various concen-
trations of the sample.
Samples of different concentrations of total suspended sol-
ids can be obtained from the sample taken by:
 diluting it with water
 depositing the total suspended solids and decanting off
the remaining water
Before measuring the samples, make sure that the total
suspended solids are actually in suspension.
8 Sort the value pairs in descending order and, if necessary,
enter them in a table and diagram (see chapter 10).