Converting Differential Results to RSE

[JLB236]

I have a USB 6008, which I am using with DAQExpress.  I have 8 analog inputs that need to be connected as RSE, but I messed up big time and did a whole test series with all the inputs set to Differential instead.  I'm a total novice with this type of testing.  I wasn't sure what sort of voltages I should be looking for, and the input channels were all seeing peaks at the expected times, so I didn't realize my mistake until I was analyzing the data.

Is there any way for me to obtain the single input readings from the differential data that I collected, or do I need to repeat the testing?

[crossrulz]

Unfortunately, you just have the difference between 2 channels, not their actual voltage.  You will have to rerun your test.

[JLB236]

I saved the data from both the positive and negative differential channels, but both channels return very different voltages.  Which one is the differential data?

[mtillman]

Hi, 

The voltage measurement will be the difference between the positive and negative terminals. For instance, if the positive channel reads 5V and the negative channel reads 1V then the differential measurement would be 4V. 

I have included a tutorial that explains the differences between RSE and differential measurements for your reference.

How to Measure Voltage

https://www.ni.com/en/shop/data-acquisition/sensor-fundamentals/measuring-direct-current-dc-voltage....

Best, 

Megan T. 

Technical Support Engineer

National Instruments