Endress+Hauser MMP20 SONO Mobil, Руководство по эксплуатации

Страница: 32 / 64

MMP20 SONO-DIS (option D)
Page 32 Hauser
Step 3. Insert the SONO-WZ lance probe into the fresh concrete and start an individual
measurement
Make sure there is no trapped air in the fresh concrete.
Pay attention to the two different procedures for inserting the probe into plastic concrete F2/F3 and
more liquid concrete up to flow class F6. These are documented in the information sheet.
F2, F3 and F4 concrete: Insert the probe at the edge of the bucket at a slight angle, compacting it
somewhat by tapping the bucket.
F5-F6 concrete: Use of the W/C shovel. Insert the probe vertically into the concrete at the edge of
the bucket and slowly slide the probe tip diagonally to the opposite side of the bucket so that there
is a representative concrete mix around the probe.
Press the " Start measurement " key to take the first single measurement. This takes approx. 2
seconds (with rotating symbol shown on the LCD). The water content, determined using the raw
density, is calculated in l/m 3 and displayed. No. values indicates the number of individual
measurements that have been taken. The Meas menu:
To obtain a representative value for the material mix, it is advisable to take at least 4-10 individual
measurements - depending on the concrete formulation - as described under the section
"Measurement of laboratory samples in a bucket". Large gravel pieces directly at the surface of the
probe can influence individual measurements; a lower water content would be measured, for example.
In the case of concretes that tend to bleed, we strongly recommend taking a higher number of
individual measurements, as this increases the accuracy and makes for a more representative
value!
The standard deviation Std-Dev displayed by the SONO-DIS is a reflection of the quality of the read-
ing. If the Std-Dev value is greater than 0.5, the concrete mix is so heterogeneous that it is recom-
mended to take more individual measurements. At least 4-5 single measurements should be taken
and a
Std-Dev less than 0.5 should be displayed before you should stop taking single measurements
and accept the measured value as the final result.
It is very difficult, however, to achieve a
StdDev less than 0.5 for very heterogeneous concretes
(e.g. concretes that bleed). SONO-DIS automatically filters out water content values that are less
than 100 liters. This can happen, for example, if the start button is accidentally pressed during
a measurement series or if the probe was not yet fully introduced into the concrete. As they are
too low (<100), these values are flagged with a warning sign
and are not used to calculate
the average!
Smileys on the display screen indicate whether the standard deviation is good
(<0.2), acceptable (0.2 to - 0.49) or not acceptable (>0.5).
Remaining
battery
Water content as an
average value
Pressed briefly:
Delete last measurement
value
Pressed for longer:
Delete entire measure-
Number of
measurements
performed
Conductivity /
assessment of the cement
Standard deviation :
More single measurements
are needed if the std-dev >0.5!
Set new parameters
Last measured value
(can be deleted)