Use both Radar and Ultrasonic Level Transmitter

[Morteza Sadeghinia]

Hi,
We want to use two level transmitters with different principle on a drum and it's been decided to use non-contact radar and ultrasonic level transmitters.
I know that there are other alternatives like dp and displacer but the question is that "Does electromagnetic wave of radar level transmiiter and sound wave of ultrasonic level transmitter interfere with each other?"
There are space/distance limitations on top of the drum and that's why this issue has been raised.
Thanks.

 

[thebard3]

One should not interfere with the other.

Brad Waybright

The more you know, the more you know you don't know.

 

[itsmoked]

Nope, no interference.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[IRstuff]

The signals won't interfere with each other, but you need to make sure that the RF environment is compatible with the ultrasonic detector's electronics.

TTFN (ta ta for now)
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[danw2]

Some considerations for these marvels of technology.

Neither technology is very good at handling foam on the top of a liquid. Ultrasonic usually bounces off the top, radar bounces at some indeterminate point depending on the radar technology and the foam density. There's no application chart for foam, it's an empirical test to see what the functionality of either technology is.

Both technologies reflect off sidewalls and objects like ladders, creating false echoes. There are generally algorithms for accounting for permanent structures whose echoes are always the same.

Each can have varying speed-of-response, model/technology specific. Are both fast enough to register the process changes?

The deadband below the transducer fact in which a return signal can't be reliably read has reduced over time for the most recent generation of radar (some brands) but is still close to about 10" or a foot for ultrasonic. Can the installation tolerate the deadband?

Ultrasonic can not handle any vacuum or pressure over atmosphere without significant error or loss-of-echo due to speed-of-sound variations. Is that deal killer?

Ultrasonic is worthless in an atmosphere of Carbon dioxide. Just does not work.

Although some ultrasonics have an adjustment of speed-of-sound in a given atmosphere, that's fine for temperature when the adjustment is made, but there's no accounting for change in speed-of-sound for other temperatures and speed-of-sound varies by temperature. Is the process atmosphere in the vessel constantly isothermal at a fixed temperature?

Boot-up time for initialization on a couple radars I've worked with is about 45 seconds before the initialization 4.0mA output drives to a valid value. Is initialization time a factor?

Radar will shoot through a plastic vessel and bounce off a ladder laid against the outside of the tank, providing false level readings. Ask me how I know.

In an open-to-atmosphere vented tank (a requirement for ultrasonic), high relative humidity will condense on fall or spring days when the temperature drops below dewpoint, depositing condensed water on the face of the transducer or antenna which can affect either technology.

 

[Morteza Sadeghinia]

I am quite confident that both principles are suitable for this application but because I have both of them on top of the tank and close to each other, I don't know whether their waves affect each other.

 

[IRstuff]

Again, the signals won't interfere with each other

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[xnuke]

Radar uses electromagnetic waves. Ultrasonic uses air pressure waves. It seems that you don't believe the above repeated posts stating they won't interfere with each other, which are correct, so I'll ask: Why would you think that these two types of wave transmission using different principles and traveling in different media would interfere with each other?

xnuke
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