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boolean crossing question

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You only have to add a small logic to Crossrulez's design to trigger it only once... attached image shows how.  (However, this will require you to stop the VI and start again if you want to repeat the functionality - since "first time?" function is only true the very first time it is executed in a program.

 

-DP

 

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Message 11 of 32
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Or to put it all in boolean logic...

 

I used another feedback node to keep track if the F->T was already detected.


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Message 12 of 32
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Can you help me with the function of "boolean crossing"? could you give an example of how to use it please

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Message 13 of 32
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@alda wrote:

Can you help me with the function of "boolean crossing"? could you give an example of how to use it please


Are you talking about this function? What is your question? What are you trying to do?

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Message 14 of 32
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my question is to know how this block works (boolean crossing). What I'm trying to do is an accountant, accountants and have done with other functions but I want to do it with (boolean croosing) could give an example of operation of this function (boolean croosing)? since I can not find the way to the exit of the function finds a real state despite already put timers to see the output carefully. Thanks in advance

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Message 15 of 32
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I don't know what an accountant is (in the context of a LabVIEW program).

 

Your explanation is not clear at all (what are "other functions"? What function are you trying to "exit" and what does that even mean? What is a "real state"? Where did you "put timers"? What output did you want to see?).

 

Please show us your code to illustrate what you are trying to do.

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Message 16 of 32
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@alda wrote:

my question is to know how this block works (boolean crossing). What I'm trying to do is an accountant, accountants and have done with other functions but I want to do it with (boolean croosing) could give an example of operation of this function (boolean croosing)? since I can not find the way to the exit of the function finds a real state despite already put timers to see the output carefully. Thanks in advance


The function that Altenbach gave a link to keeps track of what the previous data point you gave it.  Then based on the direction you are looking for, it does the comparison of the new value with the old and your output is just a Boolean that says that that condition was found.

 

What part of the function are you not understanding?  Play with it.  You'll learn a lot more that way.


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Message 17 of 32
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the only thing I want to know is how this feature works, since I've been practicing with that function only I get 0 in the output. could you give an example of how to use it since the aid on the menu labview did not understand him.
sorry for not explaining well. and I speak Spanish.

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Message 18 of 32
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Are you constantly getting a 0 out of the Read function (not sure where that came from)?  You might want to add a wait in your loop to verify that you never see the rising edge.  It could be cycling so fast that you just don't see it.


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Message 19 of 32
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If indeed always get a 0.Lo that I want now is to find a 1. For that reason I like to understand how the block works "boolean croosing".What you suggest and try using the button "Highlight Execution " on the back panel.

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Message 20 of 32
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