Increase the analog voltage output within a loop using buffered hardware timing

[LiangLee]

Hi all, I try to generate a increasing voltage within a loop, voltage increases by 0.5v in each cycle. (Because I need to synchronous control, the cycle time need to be customized) But my device (USB-6289) don't support non-buffered hardware-timed operations. Can my device reach this goal using buffered hardware timing?

[Kevin_Price]

Sure.  Based on your drawing, all you need to do is configure your AO task to use your "sync" pulse as an external sample clock.  Then write your incrementing voltage values to the task buffer and start the task.

-Kevin P

[LiangLee]

Dear Kevin, thanks for your reply. I am new to labview and try few times to solve this problem, but it doesn't work. I have deleted some vi in the picture. Could you please decribe in more detail how to configure the sample clock and write incrementing voltage values to the task buffer?

[Kevin_Price · Accepted solution]

Below is an *incomplete* illustration of the key things you'd need to do.

1. Configure DAQmx Timing to use your external Sync pulse signal as a sample clock

2. Use the 'Ramp Pattern' function to create an array of incrementing voltages

3. Write the whole array to the task

4. Start the task

-Kevin P

[LiangLee]

Oh, it works. That's what I want. Thank you very much, Kevin. 😉

[LiangLee]

Hi, I have found a new problem now. If I generate a big array. When the loop executes certian times, the loop execution speed will turn slow. What‘s the reason? Expect to your reply.

[LiangLee]

More details here: https://forums.ni.com/t5/LabVIEW/non-regeneration-analog-ouput-within-a-loop/td-p/4221271