CO Pulse Time

[穆易]

How to use DAQmx CO Pulse Time to change duty continueously while not stop task?

[GerdW]

Hi Asian guy,

use DAQmxWrite to set new frequency and duty cycle…

LabVIEW and DAQmx come with a huge example library, and there are also exampleVIs on DAQmx-CO tasks!

[穆易]

This is an example from labview library, I use a card USB-6210, but I get this error as below:

[GerdW]

Hi,

that error description is pretty self-explanatory, so why don't you follow it?

[穆易]

I get no error by this code, but this can only output the first setting pulse. How to do?

[JensG69 · Accepted solution]

Try something like this:

Regards, Jens

[Kevin_Price · Accepted solution]

Two points:

1. Your device is an M-series MIO board which does *not* support buffered pulse train output.  If you need to predefine a buffer of pulse params and then generate those pulses with hardware timing, you'll need a newer device such as an X-series board (model #'s 63xx). 

2. The post from JensG69 points you in a useful direction -- consider changing pulse params based on software timing.  However, be aware that the code may not *quite* work as-is.  You may find that you need to write *both* frequency and duty cycle in order for the duty cycle to update.  (This was definitely true some years ago, but it's possible DAQmx has changed to no longer require it.)  FYI, in case you don't see duty cycle changes take effect in you pulse train signal.

-Kevin P