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Digital signal/channel always has period 50Hz/ How can I set up working digital channel?

Hi!

I want to put out a digital waveform of 0´s and 1´s on port0/line0 of my Ni6259. As Trigger I want to have the 20MHz timebase or a divisor of it (haven´t figured out yet how divsion of timebases works as well, does anyone know?).
I made a boolean array with 1000 entrys and use it as digital signal. I set up a digital output channel with finite samples and number of samples is 1000, sampling rate is 1000Hz. Next I got a while-loop with daqmx-write, -start, -wait until done and - stop in it.
My signal output is given to an oscilloscope. In my array the first entry is 1, all others are 0.
The problem is, that the peaks come with about 50Hz and I don´t know why. The peak is 50ns long, which is ok with 20MHz and if I set a one as last entry in the array, I can see, that first and last peak have 50us time in between, which is ok, too with 1000 samples. Changing the sampling rate doesn´t do anything.
For my understanding, the signal generation should start over again depending on sampling rate.
Can someone help me with this problem?
If something is not understandible, please ask.

Regards,
Yopp
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Hi,
 
you find here links to digital pattern
 
 
 
when you wants create a controllable digital pattern (0/1signals) you can also use one counter task -> his counter output set as source for the digital task (Timing.vi - Sample Clock) and so you controll with counter pulses the digital outputs (so as in example with analog input by you as digital output task)
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Johann, thanks for the replay. I´ve seen both the articles that you´ve linked but they didn´t help me. I´ve also found the exmaple VI you attached yesterday and changed it to my needs, but had the same problems with it.
Anyway, I think I have to generate the signal in continuous mode to get to where I want.

Regards Yopp
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