USB 4431 DC Voltage Sweep Analog Output

[tantradnya]

Hi All,

I have NI USB 4431 Dynamic Signal Analyzer. I want to generate constant DC voltage on AO0 port of this hardware. I tried to use Gen Voltage Update.vi sample but it says that HW Timed Single Update mode can not be used with this hardware.When I use Test Panel from MAX, I can generate constant DC voltage.

How do I make it happen in Labview? Can someone help me out ?

[lddyuhb@163.com]

I have the same problem with you,who can tell me how to generate the DC value in labwindowsCVI? the code works well with other device(USB 6353),but it occurs error. 

[Mcdan · Accepted solution]

The USB 4431 can be used to generate a DC voltage, though to do so you actually need to create a hardware timed task.  This is because it uses a delta-sigma DAC which must be clocked to produce output.  To do this, I would recommend that you configure the device to perform a finite generation.  The data you'll write is just the DC value that you want to output, repeated.  Then, you'll want to set the AO.IdleOutputBehavior property.  In LabVIEW, this is found in DAQmxChannel->Analog Output->General Properties->Output Configuration.  In the C API, you'd call DAQmxSetAOIdleOutputBehavior to DAQmx_Val_MaintainExistingValue.

To summarize:

1) Create finite output task

2) Configure IdleOutputBehavior property

3) Write data (DC Value, repeated)

4) Start task.

This should result in the desired DC value being output.

Hope that helps,

Dan

[tantradnya]

Thanks a lot. It worked like a charm.

[harishravi123]

Hello, could you please elaborate your answer? I am new to Labview and couldn't create a vi to acheive the same. It would be great if you can provide a sample vi.

[Mcdan]

harishravi123,

I don't have a 4431 to test this VI with, but it should give you the general idea.

Hope that helps,

Dan

[harishravi123]

Thanks a million, it works perfectly. Just had to change it to analog single channel instead of multiple channel and change the limits to 3.5 to -3.5 V.