strain gage measurement

[shanaka]

Hi all,

i want to measure the strain on the surface of a pipe which would carry fluid and give an alarm before it exceeding the limit.so i decided to use half bridge configuration with a dummy gage to compensate the thermal expansion. but i'm new to cDAQ .so can anybody guide me to do this task, such as what kind of module i should use and how to configure, etc.

thank you,

regards

shanaka 

[GarPar]

Hi Shanaka-

     There is an incredible Developer Zone Tutorial that walks through strain measurement fundamentals, strain measurements with National Instruments hardware and strain measurement application examples.  It can be found here.  It recommends using the NI 9237 C Series module in your cDAQ chassis.

     Additionally, if you are using LabVIEW, there is a great example program that is entitled Acq Wheatstone Bridge Samples - NI 9237.vi.  In LabVIEW, click on Help»Find Examples.  When the example finder loads, open Hardware Input and Output»DAQmx»Analog Measurements»Strain.  There are a few examples in this folder including the Acq Wheatstone Bridge Samples example.  This program shows you exactly how to hook up strain gauges with different configurations, then acquires the strain and displays it on a graph.

     This should get you off to a good start.  Best of luck with your application!

[shanaka]

hi Gary,

Thanks for your information.i also thought of going with NI9237 but before going to that,its better to play with SCXI 1520 where i can try for all three bridge configurations.i have gone through most of the documentations in NI site regarding strain measurements. i will go through the examples and let you know if i have any doubts about it. still i have less information about the pipe material and etc. so that i cannot select anything for the time being.

thank you very much for you help and i will looking forward to contact you on the forum.

Regards,

shanaka 

[GarPar]

Hi Shanaka-

     You can perform measurements on the 9237 in all three configurations as well (full, half, and quarter bridge).  Look at the LabVIEW example I referenced above to see a pinout diagram of how to hook up each configuration.

     Either SCXI or cDAQ will work - it just sounds like you already have a cDAQ chassis, so I recommended the 9237.

     Great to hear from you again, and thanks for using our forums!