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Member
10310
Posts: 12
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Re: Triangle waveform

Thank for your help

I 'll show show where it differnt on "Different.jpg".

And the other question, why I get digital signal only p0.0. I didn't the other port.

Thanks

Knight of NI
Dennis_Knutson
Posts: 33,781
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Re: Triangle waveform

As I said in my last post, I did notice the difference. No need to post a picture.
Member
10310
Posts: 12
0 Kudos

Re: Triangle waveform

I want 3 signal but I don't know how to set channels in front page.
Thanks.
Knight of NI
Dennis_Knutson
Posts: 33,781
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Re: Triangle waveform

Do you see where the physical channel name is Dev1/port0/line0:7? That means you want to use lines 0 through 7 (8 lines). If you wanted to use lines 0 through 2 (3 lines) then you would use Dev1/port0/line0:2. You can also specify something line Dev1/port0/line0, Dev1/port0/line2, etc. You also have the littel arrow on the right side of the physical channel control. Click on that and then the 'Browse option. You can use CTL-click of shift-click.
Member
10310
Posts: 12
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Re: Triangle waveform

Thanks for your help.

I do that you suggest me.But I get signal only port0.0. The other ports (port0.1-p0.2) aren't generate a signal.What 's wrong with my VI. Please you tell me.

And other question the signal that I get is not same graph that I get in the front page.What wrong with my VI.

Thanks.
Member
EGMU
Posts: 6
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Re: Triangle waveform

I have a problem. I try to compare sine wave and trangle wave at low frequency. the triangle is go to the max of amplitude that I insert. but when I insert a high frequency of triangle. A max of frequency (1k hz+)is not max that I insert. Why it not max? Please tell me. Thanks
Knight of NI
Dennis_Knutson
Posts: 33,781
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Re: Triangle waveform

Increase the samples/second.
Member
sadhoobagh
Posts: 8
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Re: Triangle waveform

Hello Everyone

 

I used Mr Michael's code to implement SPWM in LabView. I sent the output to the digital channel of ELVIS II kit. At low frequencies upto 10 Hz, my code outputs proper values. However as I increase the frequency, the output waveshape is correct but the frequency is wrong. While the output should occur at 2000 Hz, the scope shows a reading of 15 or 16 Hz. Please help me troubleshoot. I am attaching the corresponding vi.

Member
James-D
Posts: 73
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Re: Triangle waveform

Hi sadhoobagh,

 

I think I'm going to ned a little more information on your precise set-up. What troubleshooting steps have you tried so far? Is it the ELVIS II+ oscilloscope that you are viewing the signal on? How do you know that for low frequencies the code is giving the correct values?

 

Regards,

James D.
Applications Engineer
National Instruments
Member
sadhoobagh
Posts: 8
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Re: Triangle waveform

Hi James

 

I have made different codes for removing the problem of low frequency but every program outputs only low frequency. I am attaching one more code which has the same problem. The ELVIS oscilloscope was ON during the whole duration. When I dumped the output on the Analog channel of ELVIS, the output was of correct magnitude and proper frequency. However since I require atleast 8 output signals and ELVIS has 2 analog channels hence I need to output at the digital channel only.  Till 10Hz the output signal frequency matches the expected value and the same is obtained on the scope.