Flowline LI40-1001 PodView - Manual (Page 8)

8 of 16 MN204260 Rev A
UNDERSTANDING PODVIEW® Step Six
Linear vs. Non‐Linear: Two of the shapes (Vertical Cylinder Tank and Rectangular Tank) will always provide a
linear output, regardless of selecting Distance or Volume. The remaining four shapes (Vertical Cylinder Tank
with Cone Bottom, Horizontal Cylinder Tank with End Caps, Horizontal Cylinder Tank with Spherical End Caps
and Spherical Tank) will have a linear output when Distance is selected, but will have a non‐linear output when
volume is selected.
Vertical Cylindrical Tank
In the above illustration, 10” of liquid will always
be equal to 100 gallons of liquid (1” = 10 gallons).
Horizontal Cylinder Tank with End Caps
In the above illustration, 1” of liquid does not
equal 10 gallons. The 10” at the bottom
represents a rise of 62.8 gallons where the change
between 10” and 20” represents an increase of
109.6 gallons.
When volume is selected, the 4‐20 mA output from the sensor will be proportional to the volume of the tank,
not the height of the tank. This means that the current output will track the volume of the tank (in gallons or
liters) within a non‐linear tank (Vertical Cylinder Tank with Cone Bottom, Horizontal Cylinder Tank with End
Caps, Horizontal Cylinder Tank with Spherical End Caps or Spherical Tank).
When connecting the 4‐20 mA output to a display, the current signal will follow the volume of the tank. The
display will also reflect the volume of the tank and not the height of the liquid.
Example #1 (Volume Output): In the illustrations above, @ 20” of liquid, the display will show 200.0 gallons in
the Vertical Cylindrical Tank. However, in the Horizontal Cylinder Tank with End Caps, the same level of 20”
would show 172.4 gallons.