Flexim FLUXUS F704**-A2 Series, User Manual

Page: 136 / 192

FLUXUS F70x 15 SuperUser Mode
136 UMFLUXUS_F7V4-6-2EN, 2017-10-01
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.
• the LED of the measuring channel will light red (FLUXUS F709)
• 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 upper
limit used for the evaluation is the greater of the following values:
• fixed upper value, default: 1 848 m/s
• value of the sound speed curve of the medium at the operating point plus offset, default offset: 300 m/s
In the SuperUser mode, the values can be defined for media that are not contained in the data set of the transmitter. Se-
lect
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. 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 for each measuring channel the fixed upper limit of the sound speed. Enter
0
(zero)
to use the default value of 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.
A: Gain threshold
Fail if > 90 dB
GAIN=91dB → FAIL!
A: Bad soundspeed
thresh. 2007 m/s
A: Bad soundspeed
offset: +321 m/s