KROHNE MFC 300 EN - Manual (Page 106)

6
OPERATION
106
MFC 300
www.krohne.com 02/2012 - 4000498602 - MA MFC 300 R03 en
6.5.7 Pipe diameter (menu C1.1.3)
The converter can also provide the flow velocity based on a pipe diameter which the customer
can freely program. This value can either be the inner diameter of the measuring tube (factory
default) or the inner diameter of the process pipe.
6.5.8 Concentration measurement (menu C2)
This menu is used to enter the password to activate concentration measurement (in case the
concentration option is purchased) after the meter is delivered.
6.5.9 Flow direction (menu C1.3.1)
This function allows the operator to set the direction of flow in relation to the arrow on the
sensor electronics housing. If "forward" is selected, the flow direction corresponds to the "+"
arrow and with "backwards" the flow direction corresponds to the "-" arrow on the sensor
electronics housing.
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.
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.
INFORMATION!
Please refer to the separate concentration manual for further details of concentration
measurement.
Figure 6-8: Vibration behaviour during pressure suppression
1 Flow switched off
2 Sinusoidal vibration ("over-vibration")
3 Stable zero flow
.book Page 106 Monday, February 6, 2012 11:01 AM