User's Manual

1-2
Edition 1. Ref. No: 307010E
Product Description
1.2 Measurement Principle
Ullage
Level
1 ns
1 µs
Pulse sequence
Distance=c*
2
t
A LoopRadar gauge is installed at the tank top. It emits short microwave pulses
towards the product surface in the tank. The emitted microwaves hit the product
surface and are reflected back to the antenna for subsequent processing by the
transmitter electronics. The time from transmission to reception (t) is detected by
a micro-processor and is converted to the distance between the transmitter and
the product surface. The measured distance is often referred to as the Ullage.
The product level is calculated by using the following relation between tank height
and Ullage:
Level=Tank Height - Ullage.
Tank Height