16 SuperUser mode FLUXUS F808, F809
UMFLUXUS_F808_8091V1-2-1EN, 2019-08-23 145
16.4 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 amplification,
• the flow velocity will be marked as invalid. The physical quantity cannot be determined.
• the LED of the measuring channel will light red.
• a hash symbol (#) will be displayed after the unit of measurement, in case of a normal error an interrogation point (?).
Select Special Funct.\SYSTEM settings\Measuring\Miscellaneous. Press ENTER until the menu item Gain
threshold is displayed.
16.5 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 upper
limit of the flow velocity for the fluid 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 it will be corrected as follows:
v
cor
= 1.1
.
5 m/s – 0.1 m/s = 5.4 m/s, before the calculation of the derived quantities.
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. If 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 signal amplification (GAIN=) can be displayed in the upper line in
the program branch Measuring. If the current value of the signal amplification is higher
than the max. signal amplification, →FAIL! will be displayed after the current value.
Attention! The limit of the signal amplification is still active after the deactivation of the SuperUser mode.
Enter the fixed upper limit of the sound speed for each measuring channel. Enter 0 (zero)
to use the default value of 1 848 m/s.
Press ENTER.
Enter the offset for each measuring channel. Enter 0 (zero) to use the default value of
300 m/s.
Press ENTER.
A:Gain threshold
Fail if > 90 dB
GAIN=91dB→FAIL!
A:Bad soundspeed
thresh. 2007 m/s
A:Bad soundspeed
offset: +321 m/s
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