4.5
Level offset value
The calibration determines the level displayed at V0H0 for a particular head of liquid. By
entering a level offset at V3H4 the displayed value can be corrected by the value entered.
•
The offset is
subtracted from the true measured value
•
It must be entered in the units you have used for calibration
•
The analog output settings must be changed to follow the corrected
measurement.
For example, the Silometer FMX has been calibrated to display 0.0 at the level shown in
Fig. 4.5. Sometime later it is decided that the true volume measured from the bottom of
the tank is to be measured, i.e. when the liquid reaches the calibrated zero level, the
display must indicate say 250 m
3
. The value -250 is entered:
Step
Matrix
Entry
Significance
1
V3H4
e.g -250
Enter amount by which the display is to be corrected in
the units used for calibration
2
-
»E«
Register entry
3
V0H0
…
The corrected value is displayed (+250 instead of 0 at 0)
Note!
•
The offset can also be used if a linearization has been performed. In this case, the
offset is first subtracted from the »level« displayed at V0H9 and the result converted
to the volume to be displayed at V0H0.
BA119Y59
After offset = -250
Volume 250 m
3
Display 250 m
3
Before offset
Volume 250 m
3
Display 0.000
Fig. 4.5:
Effect of level offset on display at
V0H0 for level measurement
without linearization
Silometer FMX 570
Chapter 4: Calibration and Operation
22
