xy graph cutting data

[alexderjuengere]

 I would check if this anomaly was really systematic, e.g. does this look always the same over a certain period of time e.g. one week?

[glskinner84]

I put a 1.5v (AA) battery on the 9215 and got this....Is there anyway I can calibrate this daq to make sure it's still within spec?

[glskinner84]

I'm on a laptop as well.

[glskinner84]

Here's what the 1.5 looks like in MAX.

[johnsold]

That looks suspiciously like power line pickup.  How do you have everything connected, especially grounds?

Lynn

[glskinner84]

What grounds do you mean? The 2 AI grounds are going into the AI- ports on the 9215. There's nothing special set up...I'm pretty sure it's the DAQ because my DOS scope reads the 2 channels fine.

[glskinner84]

and for the AA battery I simply put the leads coming out of the DAQ in their respective polarities on the battery.

[johnsold · Accepted solution]

Try connecting the source to COM as shown on Figure 5 (below) or Figure 6 of the NI 9215 Operating Intructions and Specifications document.

Lynn

[glskinner84]

I'll post results of my attempt at your suggestion after lunch, John.

[glskinner84]

It seemed to cleanup the signal but I'm still getting a weird offset.