wheatstone bridge

[MWTK]

thanks for the explanation...

ok. my question is.. i can calculate the equation for the wheatstone bridge. so i do i apply it in labview VI so that the output could be display in osilloscope in labview VI?

please guide. and thx for prompt reply

[gnunesjr]

Yes, you can do that.  Using an oscilloscope means that you expect the signal to change in time.  Therefore you probably want to set up your VI so one of the resistance values changes in time, either under program control, or by making that resistor a slider-type control.

It sounds to me like you need to spend an afternoon getting acquainted with the basic ideas behind LabVIEW.  Try this tutorial:

http://zone.ni.com/devzone/cda/tut/p/id/7001 

That should lead you to either figuring it all out, or to some very specific questions.  You could then search the forums for help with that question, or start a new topic. 

Good luck!

-GN 

[CMal]

MWTK,

As mentioned before, LabVIEW is not a circuit design program, so you will have a hard time using it to design and simulate a circuit (as you would with any other programming language).  You may want to consider using Multisim, which IS a circuit design program.  If you have questions about Multisim, you can post them here.

Chris M

[MWTK]

thanks gnunesjr and CMal, no i not using multisim.

i just completed reading the labview tutorial... but i dont know how to start to solve my problem. 

could you give me some hints on how do to input the equation of wheatstone (to where...) so that i could measure using osi using the labview VI.

thanks

[gnunesjr]

Well, ya know, there are many ways to learn LabVIEW.  Exhausting the patience of forum contributors is probably the least effective way.  (For an example of this method, please see this famous thread.)

Here is a link with some more effective options:

http://digital.ni.com/public.nsf/allkb/7D5F60ADBFD9CDC2862572BA005DD96A

[MWTK]

i have attached my first Labview VI. I dont know whether it is correct or not?

what i am doing is to design a strain gauge sensor system.

i donno whether it's correct to use the stain conv function or not?

from the stain conv since the output is very small, so i wish to boost it up using the op-amp. how am i going to implement it 9add in op-amp) in labview?

please guide

[MWTK]

please guide

[ngyousi]

Hi MWTK,

Ed, Chris and GN are correct in their explanation and also to say that LabVIEW is not meant to be a simulation tool.

To set your expectation right, let me validate this once and for all.

LabVIEW is essentially created as a programming language to be picked up easily by engineers without programming background.

If you need a simulation tool to simulate, for example, the wheatstone bridge effect at different resistance and different amplification, you'll need a program like Multisim.

NI Multisim

http://www.ni.com/multisim/

Multisim will allow you to simulate hardware circuits in software, and combined with LabVIEW, you will be able to analyse and display results on your computer. (But that's gonna take some understanding and practice on Multisim and LabVIEW first)

As for your problem, there isn't really much to designing a wheatstone bridge for your strain sensor.

Please refer to this article for more information.

Measuring Strain with Strain Gauges

http://zone.ni.com/devzone/cda/tut/p/id/3642

Build the wheatstone bridge, use a data acquisition device and LabVIEW to acquire the sensor signal. 

What you might be more interested and concerned about is probably implementing a software amplification and filter after acquiring the sensor signal from the strain gage.

Only after you have built the strain gage and acquired the signal that you will be able to decide what you need.

This reply is also in response to the other thread that you have posted.

"Learning vi"

http://forums.ni.com/ni/board/message?board.id=170&message.id=358251

Please let me know if this information is suited for your application. I'll be glad to answer any further queries you have.

Rgds,

YOUSI

Applications Engineer

NI ASEAN

Thanks GN, Ed, and Chris for your explanations.

[MWTK]

Hi ngyousi, thx for your valuable input.

could you help me on the Learning VI thread?

Thanks

[tbob]

If I am correct in my Wheatstone Bridge application, the attached VI should calculate voltages and currents around the bridge.  Maybe this is what you are looking for.  It is still better to use some circuit design program instead of Labview for this.

tbob