L ST4 0 0 |
U LT R A S O N I C L E V EL T R A N SM I T T ER
| O I/L S T4 0 0 - EN R E V. E
3
1 Introduction
LST400 works on the non-contact principle of ultrasonics. A
pulse of energy emits from the transducer at the speed of
sound and is detected upon its return. The transmitter can
distinguish the difference between a correct echo and other
ambient noise. When the signal returns, LST400 measures the
time period and then knowing the speed of sound, it can
accurately calculate the distance from the material to the
transducer. The LST400 can measure distance, level and open
channel flow.
In distance mode the LST400 measures distance from the
transducer. This means the 20mA will be the furthest point and
the 4mA will be the closest point. In level mode the LST400
measures level in a tank. This means at the furthest point or
when the tank is empty, the instrument will read 4mA. At the
closest point the tank will be full and the instrument will read
20mA.
The Open Channel flow meter uses a level measurement from
the LST400 and converts the reading into a flow measurement
A microprocessor then controls the output functions of the
relays, display and the analogue output signals.
LST400
