Rockwell Automation 1734sc-IE4CH E+H Instruments via HART to PlantPAx User Manual - Manual (Page 134)

134 Rockwell Automation Publication PROCES-UM002A-EN-P - July 2014
Appendix J Prosonic S Transmitter
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
Measured Variables
From D results the desired measuring value:
• Level L
• Volume V
• Flow Q across measuring weirs or open channels
FDU9x
Prosonic S
FMU90
Prosonic S
FMU90
FDU9x
D
Q
100%
0%
D
L
F E
BD
V
Item Description
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