When to create a subVI

Happy new year folks
My question is based on style.
Should a SubVI be created with the view of simplifying a main VI or with the view of a general purpose. To make my question more clear i'll state an example.
I have a Cluster of 4 controls and based on the value of one control i must increment or decrement another control. Now, do i pass the complete cluster into a subVI and unbundle inside or Send in only the two controls involved in the process? because the other 2 control valuses would remain unchanged. Doing the former would make a simpler Main VI and the latter would permit me to use this same Sub VI somewhere else.Which is a better practice to use?
Thank you
Solved!
Go to Solution.

Personally, I think I may have had 2 subVIs in my CLD. If you go for the subVI, make sure it is a concise function. In the exam setup (because of time), go for the ease of reading (which will also be tidyness). In your exact example, I wouldn't make the subVI unless it was something that I would need in multiple places.
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Attachments:
Crasher.vi ‏19 KB
lvlog07-26-04-21-36-17.txt ‏3 KB

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In your program there is no need of the sequence structure or even the local variable. I have attched a modified version of the vi that gives the same results as before but this one does not crash LabVIEW 7.0 when you try to create a subvi by highlighting. On another note, it is best if you create a subvi using the connector pane. Read on help for "creating Subvis from selection" on LabVIEW help to know what are the pitfalls when you create a subvi by highlighting.
Attachments:
Crasher_modified_lv_7.0.vi ‏14 KB

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To save state in a subVI and not use that state in other subVI calls, make the subVI reentrant. When a subVI that is reentrant is called it creates a unique memory space for that subVI. This is called a clone. That memory space is where state is held for that subVI. Keep in mind that it also means that the memory footprint is going to be larger.
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Hello,
Description:
I have created a VI that reads in voltage values from the NI USB-6008 device. After putting that value into a formula, I compare the new value with an array of data and output a corresponding value (this is not too important for the problem).
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The VI currently works great. My goal is to make it into a SubVi that can read in various channels and output their values. However, when I attempt to make a subVi thourgh Edit>>Create SubVi, the subVi created requires many inputs because of the many controls I utilize in the VI.
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Attachments:
YSI_R_to_T.vi ‏379 KB

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When to create a subVI

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