This document discusses ultrasonic level sensing using transducers that emit high frequency acoustic waves and measure the time-of-flight of reflected echoes to determine the distance to the surface of a liquid. It describes the basic working involving excitation of a start pulse and detection of a stop pulse, with the time difference providing the time-of-flight and corresponding distance. It also mentions that there is a blanking zone near the transducer face where objects cannot be detected. Finally, it notes this technology is used for level sensing in tanks, containers, and various industrial equipment.

1. K.SAI ANJANEYA
MDM14B015

2.  Vibrating point
 Rotating paddle
 Admittance type
 Magnetic
 Pneumatic
 Conductive

3.  Ultrasonic
 Capacitance
 Optical interface
 Microwave
 Air bubbler
 Gamma ray
etc…

4.  Compressors
 Off highway vehicles
 Industrial equipment
 Turbines

6.  In level sensing, the transducer is mounted on the bottom of the
tank/container for which the level needs to be measured.
 The sensors emit high frequency (20 kHz to 200 kHz) acoustic
waves that are reflected back to and detected by the emitting
transducer.
 The excitation of the sensor is marked with a START pulse,
while the detection of an echo is denoted with a STOP pulse. A
microcontroller (MSP430) connected to the TDC1000stimulates
the START pulse and captures the reflected STOP pulse.

7.  The difference in time between START and STOP
pulses is called the time-of-flight (ToF)
 The net result is a distance from the face of the
transducer that is blind and cannot detect an object.
It is known as the “blanking zone”
 Time (ToF) = Distance / Speed

11.  Absolute maximum ratings:
 Recommended operating conditions:

12.  Thermal information

14. Thank you