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use of express vi's

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I am new to this group and have tried to be respectful by reading the suggested rules before posting. I have labview 7; however, my question relates to all recent versions of Labview and comparison with the older versions - I am completely open to siwtching to a different forum if suggested to. I also searched the forums for past similar messages but could not find any.

I used labview a few years ago and just recently started to use it again. The express vi's are certainly easy to program but it seems to me that they do not perform as well as putting normal vi's together to do the same function. It seems that using Labview 6.1 on my 256RAM 1GIG processor computer gives better performance than Labview 7 using express VIs on a computer with 512RAM and 2GIG processor (both laptops, same PCMCIA card and equipment, both win2000). I carefully ensure that there are not extra things running in the background in oreder to give labview the maximum resources. I feel like I should not have upgraded!

Has anyone upgrading had similar experience? Is it better to avoid the express vi's?

I am grateful for any response. Thanks, and best regards,



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Hi Robert:

I think the express vi's are bulkier than they need to be for any single application because they include code, or hooks for code, for a variety of different uses.

It seems like the express vi's were developed for new users, to make it easy for them to get their feet wet. They don't seem to offer all that much to those of us that already are familiar with LabView. I do find them very useful for learning how to use some feature or hardware that is new to me-- I use the express VI for the new feature, then open it, see what portions of the code I really need to do my particular job, and delete the rest, or more often & perhaps better, write clean code from scratch using the techniques exposed in the express vi as a model

That's just my opinion however, perhaps I'm wrong, and the unused portions of the express vi's don't really cost that much in time or memory. I'll be interested to hear if the rest of the forum agrees. :question:

Best Regards, Louis

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I concur with Louis, a lot of baggage is carried in the Express vi's. They are pretty cool though to get some tasks done outright in hardly any programming time at all. And the new 'signal' wire used in some is pretty handy.

IMO, LV 7 has a lot to offer over 6. If I need speed, I code my own streamlined methods and try to shy away from the 'higher level' "one shoe fits all" vi's that NI has developed.

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  • 1 month later...

I have a comment for this post even though it's a little old.

I think when you upgrade the performance will drop because more stuff is included in the LabVIEW program as a whole. Like most major programs, they add more stuff that gets loaded into memory, but your computing power gets better with time, so that usually makes up for it.

On the topic of express VI's however, they are perhaps a little bulkier, but their operation lends them to producing more streamlined code (if they're written well). The configuration part of the express VI is not included in a build of the application... it operates independently of the code that actually runs. That means it doesn't get loaded into memory unless you're developing your program. Using scripting in the configuration part of the express VI also means that actual source code can be added in or taken out depending on what options are selected. NI uses this in the NI-Scope express VI for example. Instead of having all code in the block diagram and selecting some of it to run and some of it not to run (using cases with boolean run=true/false selections), the code itself is removed. pretty spiffy.

Well written express VI's should not only make it easier on the newbie, but also increase performance. Sometimes I don't think some of them have a chance if you're looking for a sleek, streamlined specific implementation, but my opinion is that overall they work pretty well.

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