Floating voltage on USB-6210

[tnn]

Hi Every one,

I have an USB-6210, I used Test Panel to read Analog input, i didn't connected any signals at AI, it have a floating voltage.

I have tested on USB-6009, USB-6009 don't have this floating voltage.

When i connected a signal to AI on USB-6210, it read really good.
Is my USB- 6210 damaged?

Connect USB-6009 and 6210 to ComputerFloating voltage on USB-6210USB 6210 read Sine wave 6Vpp- 10 Hz

[AnalogKid2DigitalMan]

The 6210 has a high input impedance (meg- gig ohms) while the 6009 is a measly 144 k ohm.

That high impedance will tend to accumulate and hold a charge if the inputs are not connected.

Your 6210 is probably just fine.

-AK2DM

[tnn]

Hello,
Thanks for your explanation,
Do you know, why there are many different impedance in each devices, why do some devices have different impedance when device on and off?
Regards.