Valmet TS, Installation And Owner'S Manual

Page: 30 / 63

9.3. Sensitivity correction
The sensitivity of the Valmet TS total solids content
measurement has been set for municipal waste. If the
device is used to measure some other materials, it may
be necessary to change its sensitivity. A graph is used
to determine the slope of a data set, and this value then
indicates the sensitivity of the Valmet TS total solids
content measurement.
If the sensitivity of the device to the measured mater-
ial is not known beforehand, laboratory monitoring is
required. In order to determine the sensitivity with good
reliability, the laboratory results must cover a large
enough range of total solids contents. The results of
the monitoring are plotted in a graph, with Valmet TS
on the vertical axis and Lab. total solids content on the
horizontal axis.
In the example shown in Fig. 3 a linear regression
graph is drawn through the data points. The slope of
the curve equation gives the sensitivity of the measure-
ment, in this case it is 0.89.
To correct the sensitivity, select "Special functions"
-› "Sensitivity corr." and the following display will ap-
pear:
I n p u t n e w s e n s .
c o e f f = 1 . 0 0
Press "Edit/Save" and enter the sensitivity value
obtained from the graph, in this case it was 0.89. Press
"Edit/Save" to save. If the sensitivity correction must
for some reason be done a second time, remember to
take into account the already existing correction set-
tings. In practice this means that the sensitivity obtained
at the second time must be multiplied by the existing
sensitivity coefficient, and the obtained new value is
then used as the sensitivity correction factor.
Example: in the previous example, if the sensitivity
correction value obtained from repeated laboratory
monitoring is 0.9, the new sensitivity correction is then:
0.89 x 0.9 = 0.8. If sensitivity correction must be can-
celed, enter 1 as its value.
TS vs Lab
y = 0,8932x + 0,291
2
2,2
2,4
2,6
2,8
3
3,2
3,4
3,6
3,8
2 2,2 2,4 2,6 2,8 3 3,2 3,4 3,6 3,8
Lab (%)
T
S
(%
)
Fig. 3. Determining the sensitivity of Valmet TS measurement.
Installation & Owner's manual, OUL00489 V2.3 EN 30 Valmet Total Solids Transmitter