USB 6001 Analog Input problem

[AnaKra]

Hello,

I started to work with USB 6001. That device has both differential mode and RSE mode. USB 6000 which I used before has only RSE mode. So now, when I start the same program which was working perfectly with 6000 (reading analog input from sensors), does not work on 6001. I manually setup RSE mode in DAQmx, but it has no effect.

The problem is that when I have, for example, 2 channels of analog input (simple voltage reading), and I supply voltage to only one pin, the second pin also shows input, although there is nothing on it. It happens on both differential and RSE modes. However, when I check the device in Test panels in MAX, and try test output, it shows perfect output for one pin, and totally nothing on the second pin, which does not have anything - so as it must be.
 I am a little bit confused what might be the problem. Is it mulfunctioning of the device, or software problem (although it is totally same as was working on 6000)? Waiting for your feedback. Thanks!

[AnaKra]

I attach also screes with 4 channels for 4 analog input pins. Voltage of 3V is applied only to pin ai0, but other 3 pins also shows some signal. It is same in both RSE and differential modes.

[johnsold]

You are probably seeing ghosting. This is common with unused inputs or with inputs driven by high impedance sources. Search the Forums for "ghosting" to find may posts on the topic and possible solutions.

Lynn

[Mr_Engineer]

Anakra,

Make sure to ground all unused analog input channels in differential configuration. Refer to user manual of device for input connections.

Jamal