_________________________________________________________________________________________________
______________________________________________________________________________________
14/34
www.hoentzsch.com U426_flowtherm Ex_B_e_171206
5.3.2
FA -
Measurement settings
Menu -> Settings -> Sensor -> FA Input -> Measurement settings
The task to be carried out determines the parameter, medium, section and profile factor to be set.
5.3.2.1
Medium
Setting the medium:
Selecting pairs of values in the basic settings (5.3.1.1) has no impact on the measurement.
Selection:
G
= Gases, the characteristic for air/gases is applied
F
= Liquids (Fluids), the characteristic for water/liquids is applied
Use only "GF" sensors (see technical documents) for measuring in liquids; otherwise the sensor can be
permanently damaged!
5.3.2.2
Section
Setting the measuring section for measuring in pipelines for flow rate display:
Selection:
Circular
= for pipes with circular section
di/mm: enter the ID in mm
Rectangular = for pipes with rectangular section
a/mm: enter the inner surface a in mm
b/mm: enter of the inner surface b in mm
5.3.2.3
Profile factor
The profile factor PF specifies the ratio of mean flow velocity in the measuring section and the flow velocity
measured from the sensor. Requirements are: centric sensor positioning, non-rotational inlet flow and
adequately dimensioned input/output sections. (See also Documents U117 and U205)
Following profile factors are to be set for vane wheel cylinder probes (ZS..) subject to pipe diameter:
Pipe ID
in mm
PF for ZS16 (mc)
PF for ZS18 (mc)
PF for ZS25 (mn) and
ZS30 (md)
40
0.914
0.898
50
0.933
0.916
0.735
60
0.950
0.932
0.760
70
0.964
0.948
0.784
80
0.976
0.962
0.807
90
0.987
0.975
0.829
100
0.994
0.986
0.849
120
1.004
1.004
0.882
170
1.008
1.021
0.938
180
1.008
1.021
0.945
220
1.008
1.021
0.955
...
1.009
1.021
0.960
For measurements in larger free jet as well as larger ducts or measuring tubes PF = 1.000 results in the
local/punctual velocity.
With
TABLE a profile factor subject to the vane wheel type (5.3.1.1) and diameter of the measuring
surface (5.3.2.2) is recommended. This value can be verified or also amended before saving. If rectang-
ular is selected, the surface is converted to circular for the proposed value and this value is approximate.
If the sensor is a ZS18 (mc), the value must be amended according to the table above.
PF = 1.000 must always be set for FADi... measuring tubes calibrated with pairs of values!
