continuous digital source on primarily analog cards

[tingers]

It looks like it is possible to source continuous digital data on some NI DAQmx cards as described below

http://zone.ni.com/devzone/cda/epd/p/id/211#0requirements

I have the following questions about inplimentation?

1) Can the clock of the DAQmx be sourced on one of the extra digital pins for reference?

2) Would it be possible to convert the digital data pattern to 2's compliment form?

I would like to know if the same method could be used on any of the following

DAQCard-1200

6011E

6259

6034

[Austin_S]

Hi tingers,

Check out the Labview example "Correlated Dig Write with Counter" and see if that helps answer your first question.  Basically, it's using one of the counter channels to supply a clock for outputting a digital pulse train instead of using an external clock.

As far as your second questions goes, to be honest with you, I'm not sure if it'll do that or not.  I'll look into it further and let you know.

[tingers]

thanks for the info

will wait for the second part answer

[Dennis_Knutson]

You can't do it with cards that have static (software timed) digital I/O. Your manuals of those cards explain what type is there.

[tingers]

well that is a bummer. thank you for the quick response.

is the software timed digital I/O unable to hadle this do to LabVIEW's parallel nature which will result in data not always exiting the output on every clock cycle?

[Dennis_Knutson]

LabVIEW has nothing to do with it. A digital I/O board that is software timed does not any clock at all. You are subject to windows timing. The example could be rewritten but you would see a lot of jitter and be limited in the update to about 1kHz.

[tingers]

This is very good to know.

For my aplication, jitter is not a concern, and it would be fine for the system to run at 1kHz.

[Austin_S]

To help you with the second part of your question, here's a link that takes a binary number and converts it to two's complement. It's an old KB article, so it's for an older version of LV and the link to the example VI is actually broken.  However, the way to do it is the same and I've found the currentexample VI and attached it here.

Binary to two's complement: [link broken]

Also, to get your digital input into binary form:

https://www.ni.com/docs/en-US/bundle/labview-api-ref/page/vi-lib/waveform/dwdt-llb/digital-to-binary...

Hopefully this helps!