Analog Output using Waveform Timing is stopping short

[bkb]

This is a pretty abstract problem to describe, so I'll try my best.

I am given two inputs, a low ,and a high. These are voltages. I am creating a signal that will ramp from the low to the high then from the high to the low forming a pyramid. The signal I am creating is perfect. The dt of this signal is .001 because I am outputting it at 1000  Hz to an analog channel. I am outputting this to an ExpressVI analog out using "Waveform Timing" (the little checkbox with a timer on it where the sampling information is). The problem arises when I change the number of samples with this signal. It seems if I increase the samples in this signal (keeping dt and the output frequency the same, therefore increasing the DURATION of the signal), the Express Vi that outputs the singal stops short and does not process the rest of the signal.

I cannot rip out code to post here because it is not my property. Hopefully someone has experience with this and can explain how an Express VI would stop processing a signal mid-signal.

Thanks

[bkb]

The only thing I can think of is that this VI behaves like the Write measurement file and the first time you call it it "remembers" the timing in its own memory and you have to force deallocation for it to reinitialize. I will be changing the ammount of time it takes for the signal to complete each call.

[Claire_Reid]

Hi,

I saw that noone had posted a response to the forum, so hopefully this will start some activity. I will try and look into this issue and let you know what I find out.

[Claire_Reid]

Hi.

I cannot seem to reproduce this. Is there anyway to send me a screenshot of your block diagram?

[bkb · Accepted solution]

I fixed this issue.

If you use an express VI, the FIRST time you call this VI, whatever timing information you pass to it, the VI will remember it forever and it will never change. I had to replace it with low level VIs and stop/clear the task to ensure erasing this stored memory.