Controlling water level of spherical tank using labview.

Hi, I'm trying to control the water level of a spherical tank model using PID in labview. The model is a non-linear equation as follows:
Qi(t-L)-Qo=pi*R^2(1-(R-y)^2/R^2)dy/dt
where Qi=inlet flow
Qo=Outlet flow
R=tank radius
y=height of water
t=time
In order to get y, i have shifted the right hand side to the left and integrating it. However, i can't implement the integration of this non-linear equation in labview. Pls advise. Thank you.
Attached are the files that i've tried.
Attachments:
plant.vi ‏31 KB
integration3.vi ‏18 KB

I've never seen this approach before and don't really know what you're doing
from this snippet.
What you essentially have is a system where the proportionality term varies
depending on the current height of the water. This isn't too different from
heater controls where the heater can operate anywhere between 70 and 450K.
What we do here is to simply have a table of a handful of PID values
appropriate to a range of levels and simply linearly interpolate between
them to obtain an approximate value appropriate to the current level.
Control wrote in message
news:[email protected]..
> Hi, I'm trying to control the water level of a spherical tank model
> using PID in labview. The model is a non-linear equation a
s follows:
> Qi(t-L)-Qo=pi*R^2(1-(R-y)^2/R^2)dy/dt
> where Qi=inlet flow
> Qo=Outlet flow
> R=tank radius
> y=height of water
> t=time
> In order to get y, i have shifted the right hand side to the left and
> integrating it. However, i can't implement the integration of this
> non-linear equation in labview. Pls advise. Thank you.
> Attached are the files that i've tried.

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Attachments:
Sensor.vi ‏28 KB

Thinking off the top of my head, if it were me, I'd start with the master-slave design pattern.
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PS: This is homework right?
Certified Professional Instructor
Certified LabVIEW Architect
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"... after all, He's not a tame lion..."
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hello all
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N.B i am attaching the picture of the front panel.
Solved!
Go to Solution.
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Undergrad Students: Co-Op position available using LabVIEW

To Whom It May Concern:
It is good to see the recent posts about LabVIEW jobs, and we have a Co-
Op position available using LabVIEW. I recently posted a similar message
to the info-LabVIEW mailing list, and someone there recommended I also
post to comp.lang.labview.
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substantial amount of LabVIEW programming. We are looking for a EE or
computer engineering student (we aren't locked into those majors, but
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This is a cooperative education position, where students typically
alternate terms of school with terms of work experience, usually for
three terms of each. Sometimes students co-op for less than three terms,
but we prefer to have someone who can commit to three terms. Thus they
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experience.
In my previous post to the info-LabVIEW list I received a great deal of
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we are only considering students who already reside in the USA. Also, if
non-resident, you must be approved for work for a year or less in the
USA.
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Mostly LabVIEW programming, 50%-75% of the time, on custom software used
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and involves GPIB and DAQ programming. The remaining time will be spent
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[email protected]
Corning Cable Systems
PO Box 489, Mail Stop RH
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Sent via Deja.com http://www.deja.com/
Before you buy.

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crossrulz wrote:
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Message Edité par chilly charly le 10-21-2005 06:21 AM
Chilly Charly (aka CC)
E-List Master - Kudos glutton - Press the yellow button on the left...
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http://sine.ni.com/apps/we/niid_web_display.download_page?p_id_guid=E3B19B3E90B0659CE034080020E74861
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Message Edited by BrianPack on 09-14-2005 05:21 PM
Message Edited by BrianPack on 09-14-2005 05:21 PM

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Hi,
> Hi I am fighting a similar problem and so far I found this: Calling
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>
> http://sine.ni.com/apps/we/niepd_web_display.DISPLAY_EPD4?>p_guid=B45EACE3E21356A4E034080020E74861&p_node=DZ52051&p_submitted=N&p_rank=&p>_answer=&p_source=External
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I need to program a Hittite Fractional-N Synthesizer Evaluation Kit with a HMC702LP6CE an external YIG oscillator. Not sure how to use Labview to control the PLL.

Here is how to use the PLL. But I don't know of how to interact with that device
http://zone.ni.com/devzone/cda/tut/p/id/3781
And for thouse who don't know what a PLL is a free bonus link is here:
http://digital.ni.com/public.nsf/allkb/07BC8D77D4E9AE258625708B007CE74F?OpenDocument
and a second one on what that device is: http://www.hittite.com/products/view.html/view/HMC702LP6CE
Now we are all caught up to speed.
Sam S
Applications Engineer
National Instruments

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