error 200294 in Daqmxstart task

[ritch_by_nature]

I belive I solved my issues. I feed a default valid data to the shift register. I fix the axis selection issue.. but one problem I have that i cant seem to fix is the data display when I select multiple axes. If I generate a sine a square wave I think I lose some steps therefore that could mean I am losing data. That's just my opinion. You will also notice some peaks and ripples in the square waves.. I attached two pictures do you can refer to what Im talking about..

[DianeS]

Unfortunately those pictures mean absolutely nothing to me.  I see some sine waves and some square waves.  I have no idea how they correlate to the axes you want to select, nor do I have any idea what you expect your graphs to look like.

Use execution highlighting.  Use probes.  Write a small example VI that just deals with your plot selection, populate it with some appropriate data, and play with it.  Temporarily stick indicators everywhere and examine each individual waveform that you want to plot.  Delete them when you've solved your problem.

Debugging your code is one of the most valuable things you'll ever learn.  I think that it's going to be much more valuable to you in the long run to learn to debug, as opposed to having me do it for you.

I'm not trying to be mean, but I think that figuring out your last problem is well within your capability!  So hack away at it until you get it.  🙂

[JÞB]

Diane,  It looks like Update mode is "Sweep"

[ritch_by_nature]

Proven Zealot, could you elaborate. I'm still not sure how to fix that

[JÞB]

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@ritch_by_nature wrote:
Proven Zealot, could you elaborate. I'm still not sure how to fix that

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I was rushing off to a meeting.

Charts have three possible update modes:

Strip: Starts at the left and when it reaches the right side all values shift the left

Scope: Starts at the left Adds values to the right and when the end is reached the screen is cleared and starts over

Sweep: Works sort of like Scope but the old values are not deleted untill the coesponding new data over writes them (leaving discontinuities on the screen like you observe in your pictures) (AhHa!)

Right click on the chart and select "Update Mode>>" To View/Change the mode 

[ritch_by_nature]

Thanks I'll try that and see if that solve my issue. But I believe if I generate a square wave from a waveform generator there shouldn't be any spikes or noise riding at rising and falling edge of it.

[JÞB]

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@ritch_by_nature wrote:
 But I believe if I generate a square wave from a waveform generator there shouldn't be any spikes or noise riding at rising and falling edge of it.

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Depends on the generator internal design, the output impedance, and load impedance missmatch.  Thae cDAQ likely has a 1M input impedance.  a Typical waveform generator has a 50 ohm output impedance.  Did you properly terminate the generator output?  If Not, you'll get some ringing and over shoot on transitions (Just like you are seeing):smileywink:

[ritch_by_nature]

Jeff,

I am using a labview builtin function generator to a NI9263 then read that waveform using a NI 9239 both cards in the same chassis. As for the plot issue, I tried it. didnt quite fix it. Any mode I put it on I still see the problem

[ritch_by_nature]

While troubleshooting, I realized the reason the graph shows up like that is related to the index selection the the waveform array. If I choose one channels to affect with the waveform and all the rest are zeros the display come out fine. As soon as I select two channels to affect with the waveform, it does the thing that split the data in half. At least that's what the display shows. Also It is not related to the update mode of the chart.

[ritch_by_nature]

I also foudn out that when I pick three channels to apply the waveform to and the remaining 5 will be all zeros. This is what I get. From my perspective, the data is concatenated one after each other for each channel selected before being written to the daqmx write. Each color in the graph represents a channel.