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Example 3 Volume Application
A cylindrical tank with a diameter of 7 feet and a flat base that is typically
used to temporarily hold liquid, and you wish to know the volume of liquid.
You also require a high and low alarm and when the level reaches a specific
point, the vessel is pumped down, with the fluid being transferred to another
process.
empty distance (P105), 11.0 feet
100%, span (P106), 10.0 feet
85%, high alarm on (P223), 8.5 feet
80%, high alarm off (P224), 8.0 feet
80%, control (down) on (P213), 8.0 feet
15% , low alarm off (P234), 1.5 feet
10%, low alarm on (P233), 1.0 feet
20%, control (down) off (P214), 2.0 feet
In this example, there is a control relay (relay 1), which will come on if the
level rises to 8.0 feet, and go off when the level drops to 2.0 feet. (control
down). If the level rises to 8.5 feet, then the high-level alarm (relay 2) will
come on until the level drops to 8.0 feet. If the level falls to 1.0 feet, then the
low-level alarm (relay 3) will come on until the level rises to 1.5 feet.
The display will show the volume of fluid in the tank and the mA output
will be representative of Volume where 4mA = empty (0%) and 20mA =
Max Volume (100%).
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