Determining Code Width Using SCXI-1520 and PCI-MIO-16E-1

[Electromecha]

SCXI-1000
SCXI-1520

SCXI-1314
PCI-MIO-16E-1
WinXP
LabVIEW 7.1
Traditional NIdaq 7.4

Can someone help me determine the code width for a quarter bridge strain channel?  I'm trying to determine the smallest detectible change that my system can measure but I'm not sure how to combine (or get) the different gains that are applied to the incoming signal.  I'm using virtual channels so the SCXI-1520 applies some gain, and then the DAQ card applies another gain on top of that.  Is there some function like AI Parameter that I should use?   How does one determine what the AI Range is being set on the DAQ card when using virtual channels?

I understand the formulation for code width but I'm not sure how to apply it when using multiple gains from various pieces of hardware and MAX virtual channels. 

Thanks!

[Laura F.]

Hello,

Please check out this knowledgebase article about checking the gain of an SCXI module.  It also has a link to an example program that checks the gain of an SCXI module, a DAQ device, and the overall system gain that I think you will find quite useful. 

You already know the codewidth of your DAQ device and once you know the gain that is applied to your signal, you can find the codewidth associated with your strain channel. 

Please let us know if you have any questions about this.

Thanks,

Laura