13 Advanced Measuring Functions
90
UMFLUXUS_G8V4-6-1EN, 2018-10-10
13.4
Upper Limit of the Flow Velocity
Single outliers caused by heavily disturbed surroundings can appear among the measured values of the flow velocity. If
the outliers are not ignored, they will affect all derived physical quantities, which will then be unsuitable for the integration
(e.g., pulse outputs).
It is possible to ignore all measured flow velocities higher than a preset upper limit. These measured values will be marked
as outliers.
The upper limit of the flow velocity is set in
Special Funct.
\
SYSTEM settings
\
Measuring
\
Velocity limit
.
If the flow velocity is higher than the upper limit,
• the flow velocity will be marked as invalid. The physical quantity cannot be determined.
• the LED of the measuring channel will light red
• a "!" will be displayed after the unit of measurement (in case of a normal error, "?")
13.5
Cut-Off Flow
The cut-off flow is a lower limit for the flow velocity. All measured flow velocities that are lower than the limit and their de-
rived values are set to zero.
The cut-off flow can depend on the flow direction or not. The cut-off flow is set in
Special Funct.
\
SYSTEM set-
tings
\
Measuring
\
Cut-off Flow
.
If
Cut-off Flow
\
sign
and
user
are selected, two values will have to be entered:
If
Cut-off Flow
\
absolut
and
user
is selected, only one value will have to be entered:
Enter 0 (zero) to switch off the checking for outliers.
Enter a limit > 0 to switch on the checking for outliers. The measured flow velocity will then
be compared to the entered upper limit.
Press ENTER.
Note!
If the upper limit is too low, a measurement might be impossible because most of the measured val-
ues will be marked as "invalid".
Select
sign
to define a cut-off flow in dependence on the flow direction. Two independent
limits are set for the positive and negative flow directions.
Select
absolut
to define a cut-off flow independently of the flow direction. A limit is set for
the absolute value of the flow velocity.
Press ENTER.
Select
factory
to use the default limit of 2.5 cm/s (0.025 m/s) for the cut-off flow.
Select
user
to enter the cut-off flow.
Press ENTER.
Enter the cut-off flow. Press ENTER.
All positive values of the flow velocity that are lower than this limit will be set to zero.
Enter the cut-off flow. Press ENTER.
All negative values of the flow velocity greater than this limit will be set to zero.
Enter the cut-off flow. Press ENTER.
The absolute values of all flow velocity values that are lower than this limit will be set to ze-
ro.
Velocity limit
0.0
m/s
Cut-off Flow
absolut
>SIGN<
Cut-off Flow
factory
>USER<
+Cut-off Flow
2.5
cm/s
-Cut-off Flow
-2.5
cm/s
Cut-off Flow
2.5
cm/s
