All AI Channels of NI USB-6212 Reading the same value?

[midnightminer]

Hi,

I'm trying to setup a NI USB 6212.

NI-MAX and Labview (DAQ Assistant) appear to recognize the device just fine. I need to read the voltage on all 8 of the device's analog inputs. I tried setting the device up accordingly with the DAQ Assistant in labview (DAQ Assist > Acquire Signals > Analog Input > Voltage > ai0 thru ai7), but upon testing it appears that all 8 channels are reading the same voltage.

E.g., If I put 1V across ai0, the device behaves as though 1V has been put across the other 7 channels (ai1 through ai7). This goes for any channel.

This is unexpected and undesirable behavior. Could I get some assistance setting up this device such that the analog input channels are "separated", i.e. don't all read the same voltage?

Thanks. Happy to provide any additional information.

[aputman]

How is your task configured?  What do you see when you run the task from inside Max?  Are you sure that you are not configuring a simulated device (simulated devices always output the same waveform)?

[midnightminer]

I don't know - I'm pretty new to this. I don't even have a task assigned to the DAQ Assist object.

I switched over to the DAQmx read voltage, etc. sub-vi's instead of using DAQ assist and it's working now, I think.

Thank you.

[aputman]

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@midnightminer wrote:

I switched over to the DAQmx read voltage, etc. sub-vi's instead of using DAQ assist and it's working now, I think.

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Good answer.  

[midnightminer]

So I can't actually really tell if it's working. It seems as though it might be, but I'm unable to separate the channels the way I'm doing it now?

I've attached the VI I built to test this to this question. What I would like is a numeric indicator for each channel (ai0,ai1,ai2,ai3), which I can't get working. It's like I can only see one channel at a time?

[RavensFan]

What sensors do you have hooked up to each of the channels?  What values should each of them be showing you and what values are you actually seeing?

[pauldavey]

If you have nothing connected to channels 1-3, then due to the muti-plexing, you will get an almost identical signal read on those channels to what is connected to channel 0.