36
9.6.2
Consistency Check
A consistency check during the measurement is recommended.
The transducer distance can be displayed during measurement by scrolling with key
.
The optimum transducer distance (here: 50.0 mm) is displayed in the upper line in paren-
theses, followed by the entered transducer distance (here: 54.0 mm). The latter value has
to correspond to the adjusted transducer distance. Press ENTER to optimize the transduc-
er distance.
The optimum transducer distance is calculated on the basis of the measured sound speed. It is therefore a better approx-
imation than the first recommended value which had been calculated on the basis of the sound speed range entered in the
program branch
Parameter
.
If the difference between the optimum and the entered transducer distance is less than specified in Tab. 9.1, the measure-
ment is consistent and the measured values are valid. The measurement can be continued.
If the difference is greater, adjust the transducer distance to the displayed optimum value. Afterwards, check the signal
quality and the signal amplitude bar graph (see section 9.6.1). Press ENTER.
Tab. 9.1: Standard values for signal optimization
transducer frequency
difference between the optimum and the entered transducer distance [mm]
500 kHZ
15
2 MHZ
8
Enter the new adjusted transducer distance. Press ENTER.
Press key again to scroll until the transducer distance is displayed and check the dif-
ference between the optimum and the entered transducer distance. Repeat the steps if
necessary.
9.6.3
Value of the Sound Speed
The sound speed of the medium can be displayed during the measurement by pressing key .
If an approximate range for the sound speed has been entered in the program branch
Parameter
and the transducer dis-
tance has been optimized afterwards as described in section 9.6.2, it is recommended to write down the sound speed for
the next measurement. By doing this, it will not be necessary to repeat the fine adjustment.
Also write down the medium temperature because the sound speed depends on the temperature. The value can be en-
tered in the program branch
Parameter
.
9.7
Start of the Measurement
The measured values are displayed in the lower line. Press ENTER to return to the fine ad-
justment of the transducer distance (see section 9.6.1).
The outputs and the serial interface continuously receive the measured values of the corresponding channel. The results
are displayed according to the currently selected output options. The default unit of measurement of the volumetric flow
rate is m³/h. For the selection of the values to be displayed and for the setting of the output options see chapter 10. For fur-
ther measuring functions see chapter 11.
Note!
If the transducer distance is changed during the measurement, the consistency check will have to be
repeated.
L=(50.0)
54.0 mm
54.5
m3/h
Transd. Distance?
50.0
mm
L=(51.1)
50.0 mm
54.5
m3/h
Volume flow
31.82
m3/h
