Open file saved with 15.0 on another pc with 15.0

[OnlyOne]

Hello,

i created a file and saved it as version 15.0.

Then i copied this file to another pc with real LV 15.0 and there Labview detects this change:

"The VI, last saved with LabVIEW 15.0, has been converted to version 15.0.

After a VI has been saved with LabVIEW 15.0 it can only be loaded by LabVIEW 15.0 or later. 

Use Save for Previous Version... to save VIs for older versions of LabVIEW."

Is this normal?

Also the file size increses vom 50KB to 90KB when i resave the file on the LV 15.0 machine.

Does the newer LV compress the file better then LV 15.0?

Thanks

[Bob_Schor]

You ask "Is this normal?", and I answer "I've never seen this, myself."  I've moved VIs and entire Projects from one machine to another, opened them in the Version of LabVIEW with which they were last saved, and encountered no issues, no messages, and had no problems moving them back.

Actually, the previous statement is not entirely accurate -- most of the time, I don't "move" the Projects from one machine to another, I use Subversion to Checkout the current Head Revision onto another PC, but the end result is the same, I don't see an "update" message.  Some machines may even be running the SP1 release, and I don't see such a message.

Now, it must be said that essentially all of the PCs on which I open my VIs are PCs on which I, personally, have installed LabVIEW.  This includes PCs in teaching laboratories, PCs that students are using for Projects, and PCs that my colleagues are using for their own Development work.  So I'm reasonably sure that there's a consistent "level" of installation and updates (I tend to not install updates from "future" levels, i.e. I won't install a 16.0 (or higher) update on a system running LabVIEW 2015).

Bob Schor

[ML927]

Hi OnlyOne,

What do you call "real LV 15.0" on the second computer ? Do the two versions have differences ?

[OnlyOne]

The first PC has a newer version, i only execute "Save as version 15.0".

The other PC has a real Labview 15.0 installed.

So yes, the installed versions are different.

[ML927]

Ok thanks. Can you open the file with the newer version or LabVIEW or it doesn't work either ?

[GerdW]

Hi One,

i only execute "Save as version 15.0". The other PC has a real Labview 15.0 installed.

It's normal to get this "VI has been converted" message when opening VIs backsaved from a more recent LabVIEW version!

[OnlyOne]

Now one level deeper:

There is another PC that has only Labview 2015 Runtime installed (together with teststand)

a)copy a dummy.vi from runtime-pc to 2016-pc

b)save as previous 2015

c)copy it back to runtime-pc

d) then the vi is not working anymore in teststand.

But:

a) copy exact the same file from above "b" (2016 saved as 2015) to 2015-pc

b) save it (filesize increases)

c) copy it back to runtime-pc

d) file is working

Can yomeone explain this?

Thx

[pincpanter]

The interpretation seems to be straightforward: "Save as previous" does not generate a fully functional vi, only a vi that can be opened with the previous version of LabVIEW. To get a runnable vi, it is needed to actually open and save the backsaved vi, which is then recompiled.

This would also explain the message you get opening the backsaved vi for the first time.

[OnlyOne]

Thx, this makes sense.

Where can i find this in the documenation / help?

There is nothing mentioned like this in help at "Save for previous".

[pincpanter]

This is the kind of info that is hard to get in the help. To be honest, it's only my understanding of the process.

However, in a sense, it's (nearly) obvious. For the backsaved vi to be compiled, it's needed that LV2017 (for example) contains a compiler (with full optimizations and tricks) for each of the supported previous versions, which range down to LV8.0. This is obviously unlikely.

What LabVIEW does, if ever possible, is to convert the source code to a format that old compilers can digest. Then, you need the earlier development to actually compile it.