Writing to DAQmx Channel does not update phisical channel on DO card

[Jakob_Pin]

Hello guys,

I have created a program to control a valve with PWM signal.

Here I create and run the task:

And here I change the pulse width:

I can see, that the Pulse Width property does update, but on the channel does not.

I also tried this, but its the same:

What am I doing wrong?

HW info: cDAQ 9172, NI-9474.

NI-9474 card is mounted on cDAQ slot 6.

Best Regards,

Jakob

[Kevin_Price · Accepted solution]

This is a subtle one that comes up once in a while.  Here's one recent time.

Expand the property node down and *also* re-write your desired frequency value, even if it remains constant.   Writing freq is what causes the driver to use both new parameters.  Dunno why.  (Other recent experiments suggest that "low time" or "low ticks" have a similarly privileged behavior as compared to high time and high ticks.)

-Kevin P

[Jakob_Pin]

Thanks Kevin,

it works like a charm!

Best Regards,

Jakob