DAQmx Analog output gets "Missing input" when Programmatic Input is selected.

[arrowsight]

I am trying to create a sequence where a square wave signal is passed programmatically to an analog output. I am using USB-6008 DAQmx and LabView SignalExpess 3.5.0.

In either Continuous, N samples or 1 sample (On demand) the DAQmx generate analog output step complains about missing input.

How do I configure the sequence to have the square wave signal to appear on the output?

[arrowsight]

I tried using continuous samples and was able to specify the square wave signal as an input to the generate signal step.Now I am getting the following error:

Measurements: Requested value is not a supported value for this property.

Property: SampTimingType
You Have Requested: Sample Clock
You Can Select: On Demand

[TV_Enable]

Hi, 

Can you attach your SignalExpress project?  The USB-6008 supports hardware timed analog output, so you should be able to choose something other than On-Demand timing.  Just for clarification, you were able to generate an analog square wave and use continuous generation but not with a sine wave?  Lastly, are you using SignalExpress LE or the Full Version?

Thanks,

Todd V

[Dennis_Knutson]

The 6008 does NOT support hardware timed analog output. You can only specify a single point at a time. This will restrict you to software timed output of a low frequency and considerable jitter.

[TV_Enable]

Hi Dennis,

You are correct, the 6008 does not support hardware-timed analog output.  The data sheet specifies a maximum output rate of 150 Hz, which led me to believe that it could support continuous generation at that rate.  As this KnowledgeBase indicates, this device can accept software-timed updates of up to 150 samples per second.

Regards,

Todd V

[arrowsight]

Thanks Todd,

I am using the full version of SignalExpress. I have not tried to use the sine wave because it's not useful for our purposes.

I got the error that Requested value is not a supported value for this property prompting to select on demand when I tried to use the continuous samples setting.

[TV_Enable]

Hi,

As Dennis indicated, you got this error because the 6008 doesn't support hardware timed analog generation.  This is outlined in this KnowledgeBase article.  The DAQ advisor at ni.com/daq can help you find a hardware timed analog output device.  I apologize for the inconvenience. 

Regards,

Todd