15 SuperUser mode FLUXUS WW
UMFLUXUS_WWV1-1EN, 2018-02-28 107
15.4 Limit of the signal amplification
In order to prevent disturbing and/or pipe wall signals (e.g., if the pipe has run empty) from being interpreted as useful sig-
nals, it is possible to define a max. signal amplification. If the signal amplification is greater than the max. signal amplifica-
tion
• the flow velocity will be marked as invalid. The physical quantity cannot be determined.
• a hash symbol (#) will be displayed after the unit of measurement (in case of a normal error, (?) is displayed).
Select Special Funct.\SYSTEM settings\Measuring\Miscellaneous. Press ENTER until the menu item Gain
threshold is displayed.
15.5 Upper limit of the sound speed
When the plausibility of the signal is evaluated, it will be checked if the sound speed is within a defined range. The used
upper limit of the fluid sound speed is calculated from the greatest of the following values:
• fixed upper value, default: 1 848 m/s
• value of the sound speed curve of the fluid at the operating point plus offset, default offset: 300 m/s
In the SuperUser mode, the values can be defined for fluids that are not contained in the data set of the transmitter. Select
Special Funct.\SYSTEM settings\Measuring\Miscellaneous. Press ENTER until the menu item Bad
soundspeed is displayed.
Example 1: Slope: 1.1
Offset: -10.0 cm/s = -0.1 m/s
If a flow velocity v = 5 m/s is measured, before the calculation of the derived quantities, it will be cor-
rected as follows:
v
cor
= 1.1 · 5 m/s - 0.1 m/s = 5.4 m/s
Example 2: Slope: -1.0
Offset: 0.0
Only the sign of the measured values is changed.
Note! The correction data will only be stored when a measurement is started. When the transmitter is
switched off without starting a measurement, the entered correction data will be lost.
Attention! The correction of the flow velocity is still active after the deactivation of the SuperUser mode.
Enter for each measuring channel the max. signal amplification. Enter 0 (zero) if no limit of
the signal amplification is to be used.
Press ENTER.
The current value of the gain (GAIN=) can be displayed in the upper line in the program
branch Measuring. If the actual value of the gain is higher than the max. gain, the actual
value is displayed with →FAIL!.
Attention! The limit of the signal amplification is still active after the deactivation of the SuperUser mode.
Enter for each measuring channel the fixed upper limit of the sound speed. Enter 0 (zero)
to use the default value 1 848 m/s.
Press ENTER.
Enter for each measuring channel the offset. Enter 0 (zero) to use the default value of
300 m/s.
Press ENTER.
Example: fixed upper value of the sound speed thresh.: 2 007 m/s
offset: 600 m/s
value of the sound speed curve at the operating point: 1 546 m/s
As 1 546 m/s + 600 m/s = 2 146 m/s is greater than the fixed upper value 2 007, this value will be used
as the upper limit of the sound speed when the plausibility of the signal is evaluated.
A: Gain threshold
Fail if > 90 dB
A: Bad soundspeed
thresh. 2007 m/s
A: Bad soundspeed
offset: +321 m/s
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