Reading in Labview window is offset by 6V from directly reading an integrator bo

[lbs]

A digital signal from a laser is going through an analog to digital converter box and into the computer.  When we look at the signal in Labview, it is offset ~6V from reading it directly on the integrater box.  How can we get rid of this offset?

[John_P1]

Hi lbs,

Thanks for posting and welcome to the NI Forums!  Just a few questions to help me understand your application: 

1. Are you trying to measure an analog or digital signal?  I'm assuming that you are reading an analog signal that you are trying to display on a graph in LabVIEW.  "Digital signal" usually implies compliance with the TTL specification or other logic levels depending on the board you are using.  If you are using a digital input channel on a DAQ device the input will be a 1 or a 0 as opposed to a voltage level.
2. What hardware are you using to measure your signal (NI products or otherwise)?
3. What is the expected voltage and the measured voltage?  You may have the gain on your A/D converter set too high and could be clipping.
4. How is the signal from the laser being generated?  Is this a floating or grounded signal source?  How do you have your signal connected?  You may want to check out Field Wiring and Noise Considerations to help answer these questions.
5. What functions are you using in LabVIEW to read the data?  Are you using a shipping example?  You may post your code (or a screenshot) to the forum if you'd like us to take a look.

These questions should help us determine the cause of your offset.  You could always scale the data in software to eliminate the offset, but we should find out why you are receiving the offset in the first place.

-John 

[John_P1]

Also, what are you using to read the signal from the integrator box?  Are you performing an AC or DC coupled measurement?  Inconsistency here could result in a DC offset such as the one you are seeing.  Let me know more information and I'll be happy to help you further.

-John