Prosonic S FDU90/91/91F/92/93/95/96
Endress + Hauser 3
Function and system design
Measuring principle
L00-FMU90xxx-15-00-08-xx-009
BD: blocking distance; D: distance from sensor membrane to fluid surface; E: empty distance F: span (full distance);
L: level; V: volume (or mass); Q: flow
The sensor transmits ultrasonic pulses in the direction of the product surface. There, they are reflected back
and received by the sensor. The transmitter Prosonic S measures the time t between pulse transmission and
reception. From t (and the velocity of sound c) it calculates the distance D from the sensor membrane to the
product surface:
D = c · t/2
From D results the desired measuring value:
• level L
• volume V
• flow Q across measuring weirs or open channels
Time-of-flight correction In order to compensate for temperature dependent time-of-flight changes, a temperature sensor is integrated
in the ultrasonic sensors.
FDU9x
Prosonic S
FMU90
Prosonic S
FMU90
FDU9x
D
Q
100%
0%
D
L
F
E
BD
V