A simple labview question with example vi attached. Thank you very much

[sunson29]

thanks for all your notes. thank you!

[billko]

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@crossrulz wrote:

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For dataflow concepts in particular, LabVIEW Basics --> Dataflow Programming Basics.  Probably the most important concept to grasp out of that whole section is: "Remember that a node executes only when data is available at all of its input terminals and supplies data to the output terminals only when the node finishes execution."  (This applies to structures as well as nodes.  Turn the structure into a subVI and it becomes obvious as to why this is the case.)

Taken to heart, this mantra will guide you towards good LabVIEW coding practices.

[sunson29]

thanks for the details. I will study that for sure. But plz, plz allow me ask this again. I think I understand that "

1. A node (structure, function, frame, subVI, etc.) cannot execute until all wired inputs have received data.
2. A node (structure, function, frame, subVI, etc.) only places data on its output wires once everything in it has completed.
3. A loop cannot go to the next iteration until everything in its diagram has completed.

but I still don't understand why 2nd state machine can not run until 1st one stop (they are dependent)? 

[altenbach · Accepted solution]

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@sunson29 wrote:

ill don't understand why 2nd state machine can not run until 1st one stop (they are dependent)? 

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As I said, because if the green wire (did you read my entire message?)

The green wire coming out of the first loop will only have data once the first loop stops (rule 2). The case structure around the second loop (and anything in it!) cannot start until the green wire contains data (rule 1).

Are you familiar with execution highlighting mode? Try it! It will get you a better understanding.

[sunson29]

I think I got it!  Thank you! 

The true or false wire will NOT have any data unless the 1st(left) loop stoped.  

[sunson29]

Hi alterbach, 

I am going to make a new question. It's relate to this one.  Could you help me check it?  

I really really need those 2 state machine to run decently.  Because the simulation I am doing with 2 usrp rio, there are 2 state machine here, one for receiving, one for sending. I have to make it like one state machine keep running, and 2nd will run after a condition from 1st one (the true or false wire).  Thank you.