Problems with Sampling rate in LabVIEW with 1/4 bridge strain gage

[CDawgttu]

Hello,

I have a question.  I have SCXI 1001 and am trying to read strain gages and thermocouples.  In the slot 1 I have a 1122/1322 with thermocouples that works great.  In slot 2 I have a 1121/1321 that needs help.  I cannot figure out how to make a LabVIEW program to read the strain gage. 

Is computer hardware a factor?  I have a relatively old Dell, 1.7 ghz, 256 MB RAM, and all of my programs bog my machine down.  My thermocouple program with 1 functioning channel takes almost 2 minutes to load. 

Anyway, I program the DAQ assistant like I think it should be done, but I am having problems with the sampling rate.  Everytime I run the program I get an error message saying that it could not get the recommended samples in time.  I have had my delay time on my While Loop as low as .25 s and as high as 1.5 s.  I have changed my sampling rate from 1 hz to 1000 hz. 

I would really appreciate any and all help on this matter.  I am still very new to LabVIEW. <I could not contain my excitement when my thermocouple program worked>

Thanks,

CDawgttu

[Otis]

Hi CDawgttu,

I think the best thing that we can do for the moment is to try and see what the maximum rate you can get on the 1121 is, when working on its own.

According to the DataSheet the 1122 is more likely to be what's slowing you down.  There could also be some concerns with how the internal jumpers are set on the 1121, so you may want to make sure that the settings there match how you have configured your board in Measurement and Automation Explorer. 

-You can set this up by right clicking on the SCXI module and adjusting the Properties.  On the Jumpers Tab you should then make sure the values match what you've set internally (SCXI-1121 User Manual - Chapter 2)-

When you use just the 1121, see if that makes a difference in your overall application speed.

Finally, it may be easier to use an example program than the DAQ Assistant since you are using such an old machine.  You can find Strain Gauge examples by opening LabVIEW and following this path:
Help > Find Examples > Browse > Hardware Input and Output > DAQmx > Analog Measurements > Strain > Cont Acq Strain Samples.vi

I hope some of these tips get you pointed down the right path.

Regards,