Strain Gage Measurements using the SCXI-1521

[hecmar.arreola]

Hi!

I'm considering the SCXI-1521 for strain gage measurements.  New to strain gage measurements and want to make sure I'm clear on one thing.  The device specifies that this module provides quarter-bridge completion.  I'm a little hazzy on the terminology.  Does quarter-bridge completion mean that there are 3 of the 4 wheatstone bridge resistors for each channel within this module?  So that all I need is to attach the strain gage lead wires to the appropriate terminal pins for field wiring?  Or does this mean that there is 1 internal resistor, and I must provide 2 more resistors for the bridge completion as well as my strain gage for field wiring?

Thank you.

-Nic 

[RT4CY]

Hey Nic,

Thanks for posting on the NI Discussion Forums!  If you are looking to purchase a high channel count SCXI module to take several Quarter Bridge strain gage measurements, the SCXI-1521 is a good choice.  Your first thought was correct, there are 3 of the 4 bridge resistor within the module.  You will use the SCXI-1317 accessory block to connect your signals.  This 24-channel terminal block provides three terminals for each quarter-bridge strain gage channel, comprised of excitation +, analog in, and quarter-bridge. The connection diagram will look like this.



Keep in mind that this module is for Quarter Bridge strain gage measurements only.  If you decide you might need a universal strain gage module, then consider the SCXI-1520.  The only drawback is that you willl only have 8 channels (versus 24 with the SCXI-1521).  Let me know if you have any additional questions.

Message Edited by RT4CY on 09-03-2008 10:12 PM