9 Measurement
FLUXUS F808
9.3 Start of the measurement
99
UMFLUXUS_F808V2-2EN, 2020-06-25
Fine adjustment of the transducer distance
• If the displayed transducer distance is adjusted, press ENTER.
The measuring run for the positioning of the transducers is started.
The bar graph
S=
shows the amplitude of the received signal, see Fig. 9.1.
• Shift one of the transducers slightly within the range of the recommended transducer distance until the bar graph reach
-
es the max. length (6 squares).
The following quantities can be displayed in the upper line by pressing key
and in the lower line by pressing key
,
see Fig. 9.2:
•
■<>■
transducer distance
•
time
: transit time of the measuring signal in μs
•
S
: signal amplitude
•
Q
: signal quality, bar graph has to have max. length
If the signal is not sufficient for a measurement,
Q= UNDEF
will be displayed.
In case of large deviations, check if the entered parameters are correct or repeat the measurement at a different point on
the pipe.
After the precise transducer positioning, the recommended transducer distance is displayed again.
• Enter the current (exact) transducer distance.
• Press ENTER.
Consistency check
If a wide range for the sound speed has been entered in the program branch
Parameter
or the exact parameters of the
fluid are unknown, a consistency check is recommended.
The transducer distance can be displayed during the measurement by scrolling the key
.
The optimum transducer distance is displayed in brackets (here: 50.0 mm) in the upper line, followed by the entered trans
-
ducer distance (here: 54.0 mm). The latter value has to correspond to the adjusted transducer distance.
• Press ENTER to optimize the transducer 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 entered transducer distance is less than specified in Tab. 9.4, 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.
• Press ENTER.
Fig. 9.1:
Diagnostics window
Fig. 9.2:
Diagnostics window
Measuring\...\Transd. Distance\54 mm
S=■■■■■■
A:■<>■=53.9 mm!
S=■■■■■■
Q:■■■■■■■■■■■■
time=
94.0 µs
Q:■■■■■■■■■■■
L=(50.0) 54.0 mm
54.5
m3/h