Source of analog input measurement discrepancy | LabJack
 

Source of analog input measurement discrepancy

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Seth_Hughes
Seth_Hughes's picture
Source of analog input measurement discrepancy

Trying to measure six (6) analog inputs (AIN0 - AIN5), with the VS screw which is +5 volts where the even inputs are connected to the VS screw and the odd are connected to the GND screw

The discrepancy comes from AIN2-5. No matter what I do, I keep getting approximately +3.5 for AIN2 and AIN4. I get +5 for AIN0, but not the other two. 

I've attached my source code and a picture of the console that pops up showing my data. Any help is appreciated. Thank you!!

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LabJack Support
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Please remove all connections

Please remove all connections from the U6 except for USB.  Then jumper AIN0-AIN3 all to VS and view them in the test panel in LJControlPanel.  Let us know how this looks.

Seth_Hughes
Seth_Hughes's picture
They are all at 5 Volts when

They are all at 5 Volts when I did this.

LabJack Support
labjack support's picture
So now keep going and try to

So now keep going and try to see when you start to have problems.  A couple next steps that occur to me:

- Same test but run your software rather than LJCP.

- Same test but look at 6 analog inputs with the CB37.  Remove jumpers from T7, add a CB37, and install VS jumpers on AIN0-AIN5.