Hi all,
We have a USB-6216 board and I'm working on acquiring voltage data with this device.
I am working in Visual Basic 2008 with the example "ContAcqVoltageSamples_SWTimed." I have the board connected to a USB port on my Dell laptop computer that is running Windows XP.
I am observing some strange behavior with the analog inputs. To test out the system, I connect two AA batteries in series (nominal 3V) between the analog input and analog input ground (pin 28; we have screw terminal connection system). I left the minimum at -10V and maximum at 10V in all the trials I describe here. Also, I checked with MAX to make sure that it has assigned the same device number to our board as the sample code uses (dev1).
I started with ai0, which is pin 15 on our board. The VB application shows a voltage of 10.9V. Next, I tried the next analog input on the board, ai8. The application returns a voltage of 3.2, which is reasonable. I continued to connect the voltage source to sequential physical inputs on the board, which alternate between low physical channels and high physical channels. I started to notice a trend - it looks like half the channels (a0 to a7) are giving bizarre results. Some of these start at a lower value (around 4.5V), then creep up and plateau at 10.9V; others start at a negative number and go down.
I suspect this is something systemic to the board, but I may be wrong. If you feel that it's not and I chose the wrong forum board, please let me know.
Please advise what I can try to resolve this. Thanks in advance for any help.
Jason
