Flexim FLUXUS F704**-A2 Series, User Manual

Page: 97 / 192

9 Basic Measurement FLUXUS F70x
UMFLUXUS_F7V4-6-2EN, 2017-10-01 97
Repeat the steps for all channels on which a measurement is being made.
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
or a user-defined medium can be created for this sound speed (see section 13.2
and 13.3).
9.7 Start of the Measurement
If more than one measuring channel is available/activated, the transmitter works with an integrated measuring point multi-
plexer providing simultaneous measurement on the different measuring channels.
The flow is measured on one measuring channel for approx. 1 s, then the multiplexer switches to the next activated channel.
The time necessary for the measurement depends on the measuring conditions. E.g., if the measuring signal cannot be
detected immediately, the measurement time might be > 1 s.
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.
9.8 Detection of the Flow Direction
The flow direction in the pipe can be detected with the help of the displayed volumetric flow rate in conjunction with the ar-
row on the transducers:
• The medium flows in the direction of the arrow if the displayed volumetric flow rate is positive (e.g., 54.5 m³/h).
• The medium flows against the direction of the arrow if the displayed volumetric flow rate is negative (e.g., -54.5 m³/h).
9.9 Interruption of the Measurement
The measurement is interrupted by pressing key BRK if it is not protected by a program code (see section 11.11).
Tab. 9.1: Standard values for signal optimization
transducer frequency
(third character of the technical type)
difference between the optimum and the entered transducer distance [mm]
shear wave transducer
lamb wave transducer
G 20 -50...+100
H - -35...+60
K 15 -25...+40
M 10 -10...+20
P 8 -6...+10
Q 6 -3...+5
S 3 -
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.
Note! If the transducer distance is changed during the measurement, the consistency check will have to be
repeated.
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).
Note! Be careful not to stop a current measurement by inadvertently pressing key BRK!
Transd. Distance?
50.0 mm
L=(51.1) 50.0 mm
54.5 m3/h
A:Volume flow
31.82 m3/h