| Author |
Message |
Sara
electronics forum beginner
Joined: 14 Jul 2006
Posts: 1
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 Posted: Fri Jul 14, 2006 1:12 pm Post subject:
A Question about ultrasonic range meters
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Dear friends,
I'm working on a project for measuring the level of liquid in a tank
with ultrasonic sensors.
In this project i need a measurement resolution about 1mm and the
maximum range of measuring is about 4m.
First I want to know if resolution depends on the frequency of the
sensor or the electronic circuit that measures the time of going and
returning of signal.
Second I have found an article that has measured the level with phase
shift with great resolution but the maximum range is 90cm.I will
appreciate any information about this method and it's relation with
resolution and the way one can extend the maximum range to 4 m.
Thanks in advance
Regards
S.Azimi |
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zwsdotcom@gmail.com
electronics forum Guru Wannabe
Joined: 20 Sep 2005
Posts: 285
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| Posted: Fri Jul 14, 2006 1:23 pm Post subject:
Re: A Question about ultrasonic range meters
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Sara wrote:
| Quote: | shift with great resolution but the maximum range is 90cm.I will
appreciate any information about this method and it's relation with
resolution and the way one can extend the maximum range to 4 m.
|
Have several sensors spaced 90cm apart, with a float switch on each so
you can determine which sensors are not presently covered by liquid. |
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John Fields
electronics forum Guru
Joined: 24 Mar 2005
Posts: 3260
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| Posted: Fri Jul 14, 2006 3:02 pm Post subject:
Re: A Question about ultrasonic range meters
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On 14 Jul 2006 06:12:21 -0700, "Sara" <sf_azimizadeh@yahoo.com>
wrote:
| Quote: | Dear friends,
I'm working on a project for measuring the level of liquid in a tank
with ultrasonic sensors.
In this project i need a measurement resolution about 1mm and the
maximum range of measuring is about 4m.
|
---
What's the liquid and what's the minimum range?
---
| Quote: | First I want to know if resolution depends on the frequency of the
sensor or the electronic circuit that measures the time of going and
returning of signal.
|
---
It depends on both, as well as on the change in the velocity of
propagation of sound through the medium, which in turn depends on
the density and temperature of, and pressure on, the medium.
Also, you don't mention whether you'll be measuring through the
liquid or through the space in the tank above(?) it.
---
| Quote: | Second I have found an article that has measured the level with phase
shift with great resolution but the maximum range is 90cm.I will
appreciate any information about this method and it's relation with
resolution and the way one can extend the maximum range to 4 m.
|
---
Can you cite the article? Or post it?
--
John Fields
Professional Circuit Designer |
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Rene Tschaggelar
electronics forum Guru
Joined: 24 Mar 2005
Posts: 540
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| Posted: Fri Jul 14, 2006 3:14 pm Post subject:
Re: A Question about ultrasonic range meters
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Sara wrote:
| Quote: | Dear friends,
I'm working on a project for measuring the level of liquid in a tank
with ultrasonic sensors.
In this project i need a measurement resolution about 1mm and the
maximum range of measuring is about 4m.
First I want to know if resolution depends on the frequency of the
sensor or the electronic circuit that measures the time of going and
returning of signal.
Second I have found an article that has measured the level with phase
shift with great resolution but the maximum range is 90cm.I will
appreciate any information about this method and it's relation with
resolution and the way one can extend the maximum range to 4 m.
|
I guess the range depends on whether the signal can
travel in a tube or whether is is in the open.
Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net |
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Joerg
electronics forum Guru
Joined: 05 May 2005
Posts: 3533
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| Posted: Fri Jul 14, 2006 4:31 pm Post subject:
Re: A Question about ultrasonic range meters
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Hello Sara,
| Quote: | I'm working on a project for measuring the level of liquid in a tank
with ultrasonic sensors.
In this project i need a measurement resolution about 1mm and the
maximum range of measuring is about 4m.
First I want to know if resolution depends on the frequency of the
sensor or the electronic circuit that measures the time of going and
returning of signal.
|
Both. Resolution goes up with frequency but your electronics must be up
to snuff, especially if you want to extricate phase angles. Most likely
you have to become very familiar with I/Q mixing and detection. Analog
Devices and Mini-Circuits carry the relevant parts for that.
| Quote: | Second I have found an article that has measured the level with phase
shift with great resolution but the maximum range is 90cm.I will
appreciate any information about this method and it's relation with
resolution and the way one can extend the maximum range to 4 m.
|
Why was the range limited? What's the liquid? How do you focus the beam?
Anyway, before you get too carried away with achievable resolution look
at the fluid to be measured. I'd bet that it's ultrasonic properties
will not be constant over pressure, temperature etc. Look closely at the
sound velocity in it and how it changes with other parameters. This data
isn't always published but can be measured.
Then there is a whole other topic to ponder: Gas micro bubbles in the
liquid. These will scatter the ultrasound signal no matter how good you
focus the beam and influence the velocity of sound.
--
Regards, Joerg
http://www.analogconsultants.com |
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