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LCI40
Series IOM
6 oPeration
6.5 description of Functions
In most cases, the amplitude of this vibration is
below the low flow cutoff and thus does not affect
the measurement. In very few cases, the amplitude is
greater than the low flow cutoff (over-vibration) and can
cause errors with the counter values.
Figure 6-9: Amplitude Behavior
1. Low flow cutoff
2. Low flow cutoff
3. Pressure suppression
4. Pressure suppression
The pressure suppression function eliminates this effect
by activating a larger low flow cutoff
level for a short period of time. The pressure
suppression is activated when the flow falls below the
standard low flow cutoff level for the first time. For a
programmable period of time, (can be programmed in
menu C1.3.2), the pressure suppression threshold is
added to the standard low flow threshold (can be set in
menu C1.3.3).
The optimal setting values for pressure suppression
depend on the current operating conditions and can
thus only be determined on-site through testing.
6.5.10 Pressure Suppression
The pressure suppression eliminates any disruption
in the measurement in the event of an abrupt flow
switch-off e.g. when valves are suddenly closed. In
such cases, surges may occur in the pipe and in the
measuring device which could lead to over-vibration.
The flow then “swings” back and forth before a stable
zero flow is established, as shown in the figure below.
This effect occurs mainly in high pressure applications.
Vibration Behavior During Pressure Suppression
1. Flow switched off
2. Sinusoidal vibration (“over-vibration”)
3. Stable zero flow
