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LED blinking in while loop

Hi Immi,

 

Check out this 8.0 Vi.

 

 

Rgds,

Venky

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Message 11 of 18
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Hi Venky,

 

Thanks..I see only one ex-or gate with 2 switches and  a LED in the vi. I hope nothing is missing in it.

 

rgds

imran

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Message 12 of 18
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Hi Imran,

 

Yeah it is not missing anything.

It detects the transition ,whenever the Signal boolean changes its value from true to false or false to true.

Note: for help check context help (Ctrl+H) of the Edge detection.vi

 

Let me know if it meets ur requirement or not.

 

 

Rgds,

Venky

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Message 13 of 18
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Dear Venky,

 

To eleobrate my problem, i am attaching an image of the part of the vi. As you can see the information I am getting from the hardware through the DAQmx is a DBL precision number and I dont see any direct boolean signal readout from the counter. Hope this will give you a better view of the problem. I need to be able to read the logic level of the counter first in order to get the edge detection work.

 


Rgrds

imran
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Message 14 of 18
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Hi Imran:

 

Is there any reason why you cannot use a digital input rather than a counter?  This would give you a boolean value that you could use with the code from Venky.  If you do have to use a counter, can you provide some more background on what your application is doing?

Message Edited by A Person on 02-23-2009 05:27 PM
Alex Person
NI-RIO Product Support Engineer
National Instruments
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Message 15 of 18
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Hi Alex,

 

I am developing a laser ablation system for which i need a simple control of a laser equipment for generating specific number of pulses and stepping a stepper motor after each pulse (falling edge). I  tried to use a digital input but apparently the DAQ digital input is not able to detect the input pulses which are (50 us) short. Counter input detects is easily and accurately but I cannot get a logic level information from counter and  which is my basic problem. i read the help and the only way i can use digital input of my DAQ card is it to configure it as "detect changes" and hardware timed but in that case it i noticed it missed to detect some pulses and accuracy is compromised. Please bare with me as i am not an expert user of LabView.

 

regards

imran

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Message 16 of 18
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Hi Alex,

 

I am developing a laser ablation system for which i need a simple control of a laser equipment for generating specific number of pulses and stepping a stepper motor after each pulse (falling edge). I  tried to use a digital input but apparently the DAQ digital input is not able to detect the input pulses which are (50 us) short. Counter input detects is easily and accurately but I cannot get a logic level information from counter and  which is my basic problem. i read the help and the only way i can right now use digital input of my DAQ card is it to configure the advanced clock settings to "change detection" and hardware timed but in this case it i noticed it is missing to detect some pulses and accuracy is compromised. Please bare with me as i am not an expert user of LabView.

 

regards

imran

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Message 17 of 18
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Hi immi:

 

So 1 to 20 times per second, you are receiving a 50us pulse?  Your digital input should be able to detect that without a problem.  One thing you can do to help make sure you detect the pulses is to turn off the filtering as shown in the example.  Give this example a try and see if you can detect the digital pulses.  Otherwise, we can try and come up with a solution that uses a counter.

Alex Person
NI-RIO Product Support Engineer
National Instruments
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Message 18 of 18
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