Endress+Hauser Prosonic S FMU90 - Page 41

Prosonic S FMU90 Flow Measurement PROFIBUS Commissioning
Endress+Hauser 41
5.6.1 Flow N linearization
The "linearization" parameter set is used to calculate the flow from the measured level. The
Prosonic S provides the following linearization types:
• Pre-programmed flow curves for commonly used flumes and weirs
• Freely editable linearization table (up to 32 points)
•Flow formula Q = C(h
α
+ γh
β
) with freely selectable parameters
The selected linearization type determines which parameters are present.
Only the parameters "type" and "flow unit" are always present.
Flow measurement always requires a linearization.
Parameter Selection/Remarks
"type" Use this parameter to select the type of linearization.
Selection
•None
No flow linearization is performed.
Note! If this option has been selected, nor further parameters are available. A flow
measurement is only possible with one of the other options.
•Flume/weir
In this type, the linearization is performed according to a preprogrammed linearization curve.
The type of curve is selected in the "curve" parameter. Additionally, the "flow unit" has to be
specified. The "max. flow" parameter displays the max. flow of the respective flume or weir.
If required, this value can be adjusted (as well as the "width" of the weir).
•Table
In this type, a linearization table consisting of up to 32 pairs of values "level - flow" is used.
Additionally, the "flow unit" has to be specified. To enter and activate the table use the "edit"
and "status table" parameters.
•Formula
In this type, the linearization is performed according to the formula
Q = C(h
α
+ γh
β
).
The "alpha", "beta", "gamma" and "C" parameters appear, which are used to specify the
details of the curve. Additionally, the "flow unit" and the "max. flow" of the weir or flume
have to be specified.
"flow unit" Use this parameter to select the desired flow unit.
Note! After a change of the flow unit, the switching points of the limit relays have to be checked
and adjusted if required.
"curve" This parameter is available for the "flume/weir" linearization type.
It is used to select the type of flume or weir. After the selection, a second list appears with
differnt sizes of the flume or weir
1)
. When you have confirmed your selection, the Prosonic S
returns to the "linearization" function.
"twidth" This parameter appears for the curves "rectangular weir", "NFX" and "trapezoidal weir". It is
used to specify the width of the respective weir.