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acquiring data from strain gauges using a SC-2345, MAX4.4.1 and Labview8.2

Hello,
 
I'm a student doing a rersearch project at CalPoly state university in San Luis Obispo, CA using strain gauges.
We set up a new computer with a PCI-MIO-16E-4 Daq board and a SC-2345.
 
We created two channels (RSE) for strain gauges at the SC-2345 on one SCC-SG02 at channel port 5/13. We also connected a SCC-SG11 for shunt callibration, all according to the SCC-SG series manual.
 
In MAX, we created a new virtual channel and chose "acquire singals - analog input - strain".
Gage resistance: 350 Ohm
k faktor: 2.07
Quarter Bridge 1
 
The problem is, that at the very same settings for both channels, channel 5 does not show any signal if we start "run".
channel 13 works well.
We also checked both channels by creating new virtual channels for CH5 and CH13 using "voltage" instead of "strain" for analog input. (RSE, max:10V, min:-10V). At this constellation, both channels could acquire a signal, so the connection of both channels is good.
 
Could it be that CH5 does not work because it is set as "differential" on default? If yes how and where can we chance that? When we tested the channels with "test panel" in the category "devices and interfaces" of MAX, for CH5, "differential" was set as default every time we opened it. for CH13 "NRSE" was set. We changed both to RSE before we started the test.
 
The second question is, if we can also use the "voltage" setting for measuring strain gauges? we did that in the past, using LabView 6.2.
 
Can you recommend any VI for quarter bridges strain acquiring to get proper measurement results? Another problem is, that none of has ever used LabView 8.2 before.
 
I used the example VIs you can find using the Labview Help. At none of them, the shunt calibration worked. Do you know how to set up the shunt calibriation to get it work?
 
Thanks again for your help.
 
Stefan
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Stefan,
 
In terms of differential and RSE, channels 0-8 should default to differential when using test panels.  Differential needs two input channels to function correctly and these channels must be spread apart by 8 channels. (i.e channels 0 and 7 are a differential pair)  Channel 13, on the other hand, will default to rse if chosen as the reading channel because there does not exist another channel that is eight away.  I am not quiet sure if the virtual channels will default channel 5 into being differential but I will check into it.  If it is differential as default then you may run into problems since channel 13 is utilized in both strain gauge reads.   
 
"The second question is, if we can also use the "voltage" setting for measuring strain gauges? we did that in the past, using LabView 6.2."
 
If you are referring to "voltage" as acquiring a signal with custom voltage with exciation then I would reccomend using example in LabVIEW called Acq Wheatstone Bridge Samples (with Calibration).  This can be found by navigating to LabVIEW's example finder and expanding Hardware Input and Output>>DAQmx>>Analog Measurements>>Strain.

I have also included some useful links that may provide more insight into the SCC modules as well.  Also, what is the excitation voltage and power that your strain gauges are expecting?
 
Thanks,

Gio L.
Digital Support - Product Manager
National Instruments
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