Is 0.5mv signal (for full range) too small for strain gauge card?

[Ya-hoo]

Hello All,

don't have too much experience with strain gauge measurement and wonder if 0.5mv full range signal is too small for NI strain gauge card. 

Since the mechanical limitation, the max signal I can get is 0.5mv. How can I make this strain gauge measurement more accurate and possible? Does NI 9237 work for this application?

Any input are appreciated and welcome.

Thanks,

[RavensFan]

I don't think so.  A typical mV/V is about 2, so you are only looking at about 1/4th of that.  The NI-9237 is able to work with different analog input scales.  (it says it is good for up to 25 mV/V!).  So the amplification inside should be able to take care of your .5 mV/V input.

[Ya-hoo]

Hello RavensFan,

Thanks for the reply.

I need to clarify that 0.5mV is full scale signal. If 10V excitation voltage is being used, then it will be 0.05mV/V. Am I right? Is it still good?

[AlexAlligator]

Hi Ya-hoo,

We'll only be using 1/100 of the full range of the strain gauge module, but it should still be possible to measure those values. The second link below does mention that "the voltage range is actually independent of the excitation level". I hope this helps!

What Do the Units Millivolts per Volt for a Bridge-Based Sensor Mean?

How Do I Configure the Input Range of the NI 9237?

[Ya-hoo]

Very good information. Thanks,