EF200F-C
Commissioning
85
10.4.8 Configuring the low flow cut off
The Low flow cut off wizard systematically guides the user through all the parameters
that must be set to configure low flow cut off.
The measuring signal must have a certain minimum signal amplitude so that the signals
can be evaluated without any errors. Using the nominal diameter, the corresponding flow
can also be derived from this amplitude. The minimum signal amplitude depends on the
setting for the sensitivity of the DSC sensor (s), the steam quality (x) and the force of the
vibrations present (a). The value mf corresponds to the lowest measurable flow velocity
without vibration (no wet steam) at a density of 1 kg/m
3
(0.0624 lbm/ft^3). The value mf
can be set in the range from 6 to 20 m/s (1.8 to 6 ft/s) (factory setting 12 m/s (3.7 ft/s))
with the Sensitivity parameter (value range 1 to 9, factory setting 5).
The lowest flow velocity that can be measured on account of the signal amplitude v
AmpMin
is derived from the Sensitivity parameter and the steam quality (x) or from the force of
vibrations present (a).
Navigation
"Setup" menu → Low flow cut off
Low flow cut off
Sensitivity
Turn down
Parameter overview with brief description
Parameter
Description
User entry
Factory setting
Sensitivity
Adjust sensitivity of the device in the lower
flow range. Lower sensitivity leads to more
robustness against external interference.
The parameter determines the level of
sensitivity at the lower end of the measuring
range (start of measuring range). Low values
can improve the robustness of the device
with regard to external influences. The start
of measuring range is then set to a higher
value. The smallest specified measuring
range is when sensitivity is at a maximum.
1 to 9
5
Turn down
Adjust the turn down. Lower turn down
increases the minimum measureable flow
frequency.
The measuring range can be limited with
this parameter, if necessary. The upper end
of the measuring range is not affected. The
start of the low end of the measuring range
can be changed to a higher flow value,
making it possible to cut off low flows, for
example.
50 to 100 %
100 %
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