multichannel strain gage calibrication with different gage factor

[david3709]

Hello, everyone.

I just use the software, labview. I have little knowledge of this software. Now I do research work with this software for measuring the information of strain during materials deformation. I have sticked 8 strain gages on the dies. The gage factor of two of them is 2.06, another 6 is 2.04. Now I only get the program with one gage factor calibrication, 2.04 or 2.06. It is not right for the real data of strain. How can I get the seperately calibrication of these two different kinds of strain gage?

The attachment is the program of my testing.

Please help me about this problem.

[aeastet]

You have a couple of ways taht you can take care of this. You can use virtual channels that are set up in NI Max automation and explorer. You can configure each strain gage and calibrate it using the built in software. You can set each channel to different gage factors, bridge sizes, different bridges etc...

You can also set this up programically but you will have to write the code yourself to do that. The virtual channel way is going to be the easiest.

[Serge67]

The vi you attached is missing some sub vis. In particular, I wanted to see DAQmx Create Channel(AI-Strain-Strain Gage).vi I suppose that's where you set your individual channels and now it appears that all channels are set to same values specified in Strain Gage Parameters. You can change Strain Gage Information from cluster to array of clusters, where each element of the array will represent a set of parameters for a single channel, then modify the AI-Strain-Strain gage.vi to use same data type (array of clusters) and you should be in business!

Serge 

[aeastet]

This link might be helpful.

http://sine.ni.com/devzone/cda/epd/p/id/1668

[david3709]

Thanks a lot for my friends' help.

aeastet. Your advice is very helpfull.

How can I set gage factor to each channel? I am a new programmer of this software. May you help me to modify my program? I appreciate it.

Happy every day, my friends.

[david3709]

Hi.Serge

 Thanks for your hel. Can you give some detailed information about my case?

[Serge67]

Hi David,

I created an array of clusters for you in place of strain gage parameters cluster. Just remember to have as many elements in array as channels in your system otherwise the first for loop will not run for every channel. The rest of sub vis weren't available to me, so you need to modify input of the vi that gets the gage parameters array and modify the vi itself so that one array element values are set per channel. If you need help with that, attach that vi.

Serge 

[david3709]

Thanks a lot for your help, Serge.

I compare your modification for my case. I am sorry, I can not find the modification. Are you sure you send the right thing to me?

[Serge67]

Sorry, I attached wrong vi. Try this one now

[david3709]

Thanks, Serge.

In my case, there are two kinds of strain gages with different gage factor. Two of them are 2.06 and 6 of them are 2.04. You give me a gage parameter array, I can increase gage information, but how can I make sure which gage is fit to 2. 06 or 2.04? I need to make sure every gage can get its real gage factor information.