Vibration n Float Level Switch Vibration n Float Level Switch Vibration n Float Level Switch Vibration n Float Level Switch

2. TECHNOLOGIES
Guided
Wave
Radar
Radar
(Non
Contact)
Ultrasonic

3. MEASUREMENT
Radar level instruments measure the distance from the transmitter (located at some high point) to
the surface of a process material located farther below in much the same way as ultrasonic
transmitters – by measuring the time-of-flight of a traveling wave.
Radar
• Radio /
electromagnetic
waves
Ultrasonic
• Sound /
mechanical
vibrations waves
Guide Radar
• guide the
electromagnetic
waves

4. HOW IT WORK
• The time it takes for the instrument’s signal to leave the
antenna, travel to the product, and return to the antenna is
calculated into distance.
• The instrument is spanned according to the distance the 100%
and 0% points within the vessel are from its reference point.
• The measured distance can then be converted into the end
user’s desired engineering unit and viewed on the head of the
instrument or remote display.
100%
0%

5. PROCESS CONDITIONS
How do process conditions affect the reliability and accuracy of
process level transmitters ?
• density (specific gravity)?
• dielectric constant?
• conductivity?
• temperature?
• pressure?
• vacuum?
• agitation?
• vapors and condensation?
• dust and build up?
• internal structures?

6. RADAR (NON CONTACT)

7. RADAR TECHNOLOGY –
HOW IT WORKS
Radar is a time of flight measurement.
• microwave energy is transmitted by the radar.
• the microwave energy is reflected off the product surface
• the radar sensor receives the microwave energy.
• the time from transmitting to receiving the microwave energy is
measured.
• the time is converted to a distance measurement and then
eventually a level.

8. FUNCTION OF AN ANTENNA
Signal focusing
• reduction of the antenna ringing
• optimization of the beam
Signal amplification
• focusing of the emitted signal
• amplification of the receipt signal
Signal orientation
• point at the product surface
• minimization of

9. RADAR TECHNOLOGY –
WHY USE IT?
Radar level measurement
• top mounted
• solids and liquids applications
• non-contact
Radar is virtually unaffected by the following process conditions:
• temperature
• pressure and vacuum
• conductivity
• dielectric constant (dk)
• specific gravity
• vapor, steam, dust or air movement
• build up (depends on radar design)

10. RADAR TECHNOLOGY –
CHOICE OF FREQUENCY
radar wavelength = speed of light / frequency l = c / f
Frequency 6.3 GHz
wavelength l = 47.5 mm
Frequency 26 GHz
wavelength l = 11.5 mm
High frequency:
shorter wavelength
narrower beam angle
more focused signal
ability to measure smaller vessels
with more flexible mounting
47.5mm
11.5mm
Low frequency:
longer wavelength
wider beam angle
less focused signal
ability to measure in vessels with
difficult application variables

11. RADAR TECHNOLOGY – FOCUSING OF
FREQUENCY
5 GHz 10 GHz
Frequency
Comparison of horn diameters
that produce the same beam
angle
(A shorter wavelength means a
smaller antenna for the same
beam angle)
20 GHz
15 GHz 25 GHz
Focusing at 6.3 GHz:
Horn size Beam angle
3“ 38°
4“ 33°
6" 21°
10“ 15°
Focusing at 26 GHz:
Horn size Beam angle
1.5" 22°
2“ 18°
3“ 10°
4“ 8°
30 GHz
6.3 GHz 26 GHz