labview square wave measurement problem

[N.Asrih]

Hi Engeneers,

i have a problem

i've got a square wave that is 1 second high and 1 second low. High:12V Low:0V

if i put the a LED on the output the LED blinks, I want to keep that LED light on so i can see if it worked or not.

I heard that i can solve this issue with Frecuenty measurement and then put that LED on the value of that measurement.

but i dont know how to do that, im new to labview

i've made a simple VI to show my problem, the LED has to stay ON

Thanks

[GerdW]

Hi Asrih,

are you using a "real" LED or do you talk about a boolean LED indicator on a LabVIEW frontpanel?

For both you can implement this pseudocode:

led := led OR (wave>2.7V)

[N.Asrih]

a boolean LED

[GerdW]

Hi Asrih,

why do you write you expect amplitudes of 12V when your simulated signal just has an amplitude of 1?

Do the same as suggested before, but use 0.5 for comparison!

You need a shift register, a comparison and an OR function.

And for clarity I suggest recommend to stay away from ExpressVIs and DDT wires!

[N.Asrih]

Hi GertW,

it was just a simulation of my problem,

im very new to labview, so i dont know how to do that,

could you please make a VI to show me what you mean?

With kind regards,

Asrih

[GerdW · Accepted solution]

Hi Asrih,

when you are "very new" to LabVIEW you should take the free lessons provided by NI (like on learnni.com)!

Try something like this:

(It's pretty pointless as the LED will always be ON/TRUE in this example…)

[N.Asrih]

1 more question,

where did you get the value 2.7 from?

[GerdW]

Hi Asrih,

2.7V: standard TTL high level…

[N.Asrih]

Hi GertW,

Last question

I want to use this program on my ExtendedRio device (Module NI9375 DI1), The input will be high or low (12V in reality but in sortware 1 or 0).

What can i change to use this software.

With kind Regards,

Asrih 

[N.Asrih]

something like this?