why has the acquisition of Signal from DAQ an error (breakpoint) in the time axis?

[gyver.ning@gmail.com]

Hello, friends,

I have programmed to control a vibration system that is based on DAQ(NI917, NI9229, NI9263). All signals are from NI9229. when I save the data from the NI 9229 with the Write To Measurement.vi, then I find the problem in the data. The time axis for the data is not continuous, but broken. The breakpoint appear with a certain cycle, as shown in Bild "wrong time axis". It led to the signal error. i will show you a example by some charts in the appendix.   

for example , DAQ Assistant.vi have the following Timing Setting: Acquistion Mode: Continuous Samples 

                                                                                                                         Samples to Read: 1K

                                                                                                                         Rate (Hz): 25K

The acquired signal should be a continuous, as shown in chart "ideal signal (amplitude-number of measurement points)", but because the generated time axis is broken (chart "wrong time axis"), At the end, the generated signal is wrong, as shown in chart " worng sinal(amplitude-time)". 

how can i solve the problem ?

[gyver.ning@gmail.com]

has somebody a idea?

[Alex_Pi]

Hi,

This looks like you have YX pair information for drawing.

 Have you tried using a Waveform datatype which contains onle the Y information and uses a constant delta t wit t0 offset to render the X axis?

Since it is organized in Chunks, I suppose the Cunksize is 1k like your DAQ Config specified.

Do you get the wrong Information out of the VI directly? could you post a example VI so we can see what your VI is doing there?