digital waveform output

[sunny dee]

Hi,

Can someone please explain to me what the daqMX digital waveform out is? I thought I'd be able to set up a digital waveform using the supplied labview vi's and then output these using the daqMX digital waveform vi. My goal was to generate a square wave on 4 of the digital channels, but it doesn't appear to work this way.

Thanks!

Sunny

[sarahk]

Hi, Sunny.

I'll be glad to help you create the output you'd like, but can you tell me a little more about what sort of difficulties you're encountering?

In the meantime, this document from the LabVIEW help talks about the three main components of a waveform:

t0: the start time of the waveform
dt: the time interval, or duration, between data points in the waveform
Y: array containing the data values of a waveform (IE, the values at each interval on the vertical axis)

Hope this helps! Let me know if you're still having trouble.

[andrikoscy]

hi,

Sarahk and anyone, pls, if you can help me..

see the attachments..

the one attachment is the Block diagran and the other the front panel

i want to create a digital waveform without clock. this vi i created , is it true?

i connecteds the output channel with an oscilloscope and i saw, that the DAQ card didn't create the samples.

the oscilloscope showed only one line at 0 V (if i create more 0's) or in 5 Volts (if i create more 1's samples)

what can i do? any advices or ideas?..

thank you very much!
andrikos

[RavensFan]

You are missing the attachments.

[andrikoscy]

sorry,

i forgot the attachments..

[Nathan_R]

Hi andrikoscy,

With the VI you wrote it is only going to output your waveform once. The digital output will be left at the last value in the waveform. For example, if you end the waveform in a 1 then the line will stay high. In order to see the waveform with your scope you can set the scope to do a single acquisition on a rising edge trigger. Set the trigger level, start the scope, and then run your VI. This should show you the two pulses in your waveform.

For more examples of digital output I would recommend looking at the digital generation examples in LabVIEW. These can be found by going to the Help menu and selecting Find Examples.... Once the NI Example Finder is open select Hardware Input and Output»DAQmx»Digital Generation. Also if all you need to do is output a square wave I would recommend using a counter output task assuming your card supports it. A good example of using a counter to generate a square wave can be found in the NI Example Finder under Hardware Input and Output»DAQmx»Generating Digital Pulses»Gen Dig Pulse Train-Continous.vi.

Thanks,

Nathan