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time relay

I am starting to learn labview. I want to make another project to use in my home. I want to control with labview some different type of utilities. For start I want to make a vi that acts as a time relay. 

I want to select De type of relay :

I want to make him with 3 options:

-to start after a preseted time 

-to stop after a preseted time

-to wait for a preseted time, start, run for a preseted time, and then stop 

I want to see it running with a Boolean led, after that I will want to figure it out alone how to connect it from the computer to the utilities.

I am using labview 6.

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   Sounds like an interesting project. With Discussion Forums the more specific your question the better answers you will receive. Also most of the users are on newer versions of LabVIEW so they might not be sure which functions are at your disposal. In a newer version I know I would recommend Event Structures on this particular project. I hope this helps with your Discussion Forum adventures.

Ben J.
National Instruments
Applications Engineer
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Message 2 of 6
ANDRUu, I've been trying to come up with the same sort of relay/vi. Good news, I just came up with something today. I started by creating a "switch until released" switch to simulate a physical limit switch. I put together the Elapsed Time subVI with combinations of boolean arguments (not, and, or, exclusive or, etc.) until I finally got the right combination for my purposes. The VI I designed will light the LED as soon as the button (or limit switch) is pressed and it will stay lit for a set duration. It may be a little elementary, but I think that's just fine for just starting to learn labview, like you and I. I also agree that using event structures you should be able to make one subVI where you can select the type of relay, and each event loop will have the combination of ands and ors to get the desired effect. I'm going to try to attach my vi as well as a pic of the block diagram. Good luck. Ben
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Having a hard time attaching the files. Gotta love technology. It's a simple enough, I'll try to explain it in words. The switch is split. One branch goes to a boolean "AND". The second branch goes through a boolean "NOT" and into the "RESET" input of the "ELAPSED TIME" subVI. The "TIME HAS ELAPSED" output of that subVI goes through another "NOT" and into the second input of the aformentioned "AND". The LED is driven by the output of the aformentioned "AND". The whole shebang is surrounded by a while loop to keep it running. As far as the elapsed time subVI goes, the "automatically reset after time target" needs to be unchecked. Hopefully you can put something together out of my ramblings. Good luck Ben
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To attach your file all you need to do is, At the bottom of the area where you are typing your reply. (like right here!) In the left side the side opposite the POST button, there is the attachments box. Click the Browse button, then find your VI and double click on it. The path will show up in the attachments box. Hit the POST button. All done.



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I would have done that, but IT has so many restrictions on these machines it makes it hard to do much of anything. Perhaps I'll bring the files home and attach from my home PC (where I am IT).
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