subtract node in version 7 - what changed here?

[GerdW]

Hi,

I just stumbled about a curious subtract node

When opening a LV6 vi in LV8.2.1 I get such subtract nodes in the block diagram:
(Both inputs are DBL.)
This doesn't happen when opening the same vi in LV7.1...

So what has changed in LV8+ with the subtract node?


Message Edited by GerdW on 11-27-2007 10:27 AM

[parthabe]

I ve never encountered this before when I opened VIs built in LV 6.x in LV 8.21 eveluation.

But will it occur only in FDS or PDS & not in Evaluation?!

[GerdW]

Hi Partha,

I always use the PDS (universitary license )...

[tst]

I would vote for a bug. Can you right click the node and change the conversion?

[GerdW]

Hi tst,

no - there are no options to change the conversion after right-click.
I already tried this as you get similar behaviour (showing red "4.x") with some old type-casting nodes...

And here I got this funny vi (PID-Regler1.vi) from!


Message Edited by GerdW on 11-27-2007 11:10 AM

[parthabe]

I m not getting this even in 8.5.

[Gabi1]

8,2,1 i do see it also.

but it behave exactly same as a "normal" substraction (addition). so no immediate bug.
copy paste doesnt keep the (7.x). deleting the while loop or sequence also cleans it. so no way to test if there might be a different behavior. it seems dependent on the wire itself, and not so much the operation. the "responsible" wire is coming directly from the uninitialized shift register. maybe the way the functional global works has changed since LV7.x?

Message Edited by Gabi1 on 11-27-2007 11:32 AM

[Ben]

The following is a wild unfounded speculation.

LV used to have a preference for the top input of adds subtracts etc. where the top node was "perfered". By prfered I mean that the buffer holding the data for the top input could be re-used. That was not the case for the bottom input. Recent testing has implied that the top input is no longer "prefered" and either input are now available to for buffer re-use.

So....

maybe it has something to do with the old "prefered" input.

Just guessing!

Ben

[Ray.R]

That is interesting Gerd...

I can't imagine what could be different in such a basic function...  😮

[GerdW]

Well it seems someone at NI should provide some light on this...