PRECISION WAVE
PWCS70 Series Ultrasonic Level Transmitter

The w orking principle of ultr asonic le vel meter is tha t the ultr asonic pulse emit ted b y the
transducer (pr obe)is r eflected b ack aft er c ontacting the surf ace of me asured medium, and
part of the echo r eflected b ack is r eceived b y the tr ansducer and c onverted int o an elec trical
signal.
The ultrasonic pulse pr opagates at the speed of sound w aves, and the time fr om emission
to r eception is in dir ect pr oportion t o the dis tance be tween the tr ansducer t o the medium
surface. The relation between the distance D, the sound speed C and the time T c an be expressed
by the f ollowing f ormula:
D=V c×T/2
Since the tr ansmitted ultrasonic pulse has a c ertain width, the r eflected wave in the short
region ne ar the tr ansducer o verlaps with the tr ansmitted w ave, and it c annot be identified,
and the dis tance value c annot be me asured. This ar ea is c alled me asurement de ad z one, and
the siz e of ne ar blanking ar ea is r elated t o the fr equency of ultr asonic le vel me ter.