4.4 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
• All values, including analog signals and relay settings must be changed to
follow the corrected measurement.
For example, after a dry calibration, see Section 8.1, 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 m3. The zero shift corresponds
to 250 m
3
.
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
3V0H0
…
The corrected value is displayed (+250 instead of 0 at 0)
Note!
• The offset cannot 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.
BA063E59
After offset = –250
Volume 250 m
3
Display 250 m
3
Before offset
Volume 250 m
3
Display 0.000
Fig. 4.3:
Effect of level offset value
on display at V0H0 for level
measurement
Silometer FMC 671 Z/676 Z Chapter 4: Calibration and Operation
25
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