dthomson

Chris, Thanks for the ideas. Sounds like you've got an interesting system working. From what I gather, you zip the distribution to save space, then unzip it dynamically to use it? Even zipped, the Report Generation Toolkit seems bigger than I would like to distribute. Maybe someone has a third party LV tool for making PDFs? DaveT

I was wondering if anyone had come across any alternatives for creating html reports that don't use the NI Report Generation Toolkit. We're starting to play with the Report toolkit, but my previous experience is that when you create a distribution, it bundles in a huge amount of LVOOP libraries, directories, etc. We're making a built executable with plug-in modules. The report will be generated by a plug-in, and so we need to deploy all the necessary sub-vis as a source distribution. I'm reluctant to have it blow up into 10s or 100s of MB's just for a fairly simple piece of functionality. I wouldn't be surprised if people had made their own html report generation code, but so far I haven't been able to find any. Thanks, DaveT

QUOTE (crelf @ Apr 11 2008, 08:06 AM) I second that. (Or third, or whatever.) I've noticed this issue, and although I don't need it often enough to have as strong of a desire to have it automated, I would certainly appreciate having a feature built-in to the Project Manager that would allow these versions to be synchronized. DaveT

At the risk of continuing the highjacking of the thread (though in truth, the thread was already pretty far from LabVIEW and actually on a fairly related subject...) I think perhaps you overestimate both my class and my aresenal, Ben! Though perhaps not my interest or conviction. In truth, I'm not much of a debater. But I do think the issue is important, and if you were to choose to discuss it (publicly here, or in a less public format), I would hope that we might both end up learning something. As for your last point, I couldn't agree more. I have a personal opinion on the issue and a professional opinion, and I'm glad to share either one with anyone who is interested, under appropriate circumstances. Our recently-retired lab directory had a very strong philosophy in this regard and it rubbed off on a lot of us: professionally, our job is to acquire data and distill the best possible scientific understanding from it, then present that to the policy makers and the public in the most accurate and understandable way possible. I'm in the process now of transitioning to the private sector, but I'm proud of having spent almost two decades working for a government lab that is guided by that principle. Cheers, DaveT QUOTE (neB @ Apr 10 2008, 07:18 AM)

QUOTE (crelf @ Mar 31 2008, 07:51 AM) I'd be curious, Ben, to know what phenomenon you believe doesn't exist - changing climate, the anthropogenic origin of changing climate, or something else? DaveT

QUOTE (tcplomp @ Apr 1 2008, 01:18 AM) Ton, Thanks for pointing that out. You are quite right - 8.5 handles the issue directly whereas 8.2 does not. I'll work on getting the customer to upgrade. Dave

I'm trying to make some new applications Vista compatible. I'm no expert on Vista, but one thing I'm doing is putting configuration and data files in different places than I used to. Apparently you can't write to files in C:\Program Files\My App, so I'm using C:\Documents and Settings\All Users\Application Data\My App\Program (or its Vista equivalent) for config files and C:\Documents and Settings\All Users\Application Data\My App\Data for data files. So for one program, I want to have an additional config-type file in the new config folder, but with the Installation script (LV 8.2.1), I can't find a way to do that. When you build an executable, you have a lot of flexibility for determining the destination for each item, but with the Installer, you can only add destination folders that are sub-folders of the paths that are already known to the installer script. At least from what I can tell. Does anyone know of a work-around so that I could include additional support files in the installer and have them go to a particular location? The best I can think of is to have the program copy the files to the desired location the first time it is run, probably from its own installation location, which the installer can access. Thanks for any ideas, DaveT

QUOTE(crelf @ Feb 24 2008, 04:57 PM) Thanks for the update. I appreciate the info! DaveT

QUOTE(Jim Kring @ Jan 27 2007, 02:11 PM) CRelf, I am considering implementing something along these lines, and was about to post a question when I came across your thread from a year ago. Very informative discussion. Thanks to all the LAVA readers who posted. I was wondering, though, if you could update us on any progress or experience you've had since this thread was started. Thanks, Dave

QUOTE(guruthilak@yahoo.com @ Feb 18 2008, 11:54 PM) Guru, Interesting idea. However, I assumed that was what LabVIEW was doing for me. I've built whole systems on the basis of this (for sub-vi's, not for dynamicly-called VI). I use a single VI to access a resource/driver/object, and can call that VI from multiple top-level LV VI's confident that LabVIEW's scheduler will prevent simultaneous calls to the non-reentrant VI. So I guess the question is, is there any reason (other than the error I've seen) to believe that dynamically called VIs should be any different?Yen, Thanks for the idea. I wrote some test code to demonstrate this. One vi that spins its wheels with arithmetic for n seconds, with an optional second loop that reads a really big file. Two callers that each call that VI dynamically. Regardless of whether the file reading option is on, both callers operate as expected, with one minor exception: Without file reading, the second VI obviously waits for the first to finish before it starts. E.g. if they are both set to 3 seconds and both started at almost the same time, the 1st finishes in 3 seconds and the 2nd in 6 seconds. However, with file reading on, both VI's run without error and read the correct data, but their run arrows both turn blank at the same time! They don't "appear" to be sequential. So although I'm not getting the same error, maybe it is doing the same thing at some level...DaveTQUOTE(Aristos Queue @ Feb 19 2008, 12:13 PM) The whole point of a functional global is you don't need a semaphore. Only one VI can call any given subVI at a time -- if you want more than one to be able to call simultaneously, make the VI reentrant, which is, in effect, creating separate VIs for every caller. But for a non-reentrant subVI, only one caller can call at a time, so you don't need semaphores.To dthomson: Sorry, I don't have anything to say to help with your issue. I've never seen a problem with this and I'd have to see some code to make any guesses about what is wrong. Aristos, Didn't see your post until just after I replied. Given my observations with the test program, do you think that is enough to submit to NI for further investigation? Actually, I just ran it again a few times. There are subtle hints that they are running sequentially, and that it is only a front-panel update issue that turns the run arrows off at the same time. The window titles get updated about half-way through, suggesting that they run sequentially, but the windows don't get fully graphically updated until both are done since the cpu is maxed out. So I'm beginning to conclude that my demo is a bust. It should have the same basic features as the full program, but I haven't been able to duplicate the problem yet...Dave

I've got a system in which there are numerous top-level VI's running in parallel. One of them will obtain a reference to a functional global and then share that reference with other top-level VIs. Each of these VI's can then call the functional global and have it execute various commands on its data. Most of these calls are brief, but one (load a file) can take several seconds, depending on the file size. Normally, everything works fine, but if the functional global is reading a long file and another VI tries to access it, the 2nd call gets an error 1026, reference not valid. A Call by Reference is similar to a sub-vi call. I would expect that the LV scheduling system would queue up requests to the functional global like it would for any other sub-vi call. I think this works in general, when calls are of short duration. I've never noticed other 1026 errors, whereas there should have been some coincidental calls by now in al the times that the program has been running. But, if I ask the functional global to read a really large file, which takes seconds, then a simultaneous call from another VI gives 1026. I've verified this by adding a simple delay of several seconds, letting the file read finish before making the same call from the 2nd VI. That works fine, so it really seems that 1026 is returned when the VI is busy, but only when it is busy for a longgg time. I haven't been able to find documentation on this feature. It makes a certain amount of sense, but surprises me since it apparently isn't documented. Does anyone else know about this "feature"? Thanks, DaveT

QUOTE(Gabi1 @ Dec 11 2007, 04:33 PM) I think I've pointed it out before, but just for reference (in case someone decides to try it), there was something like this at least once before. See www.vibots.com It had limited success, but the fellow behind it did a pretty good job setting it up. One downside was that the competitions weren't "live". You submitted your bot program, then he ran them all and posted the results. He also posted playback files, so you could view how the match went. But it would be cool to have a web interface where you could post a bot VI and have it fight other bots that had already been posted to the site. Dave

QUOTE(Jeffrey Habets @ Nov 8 2007, 04:55 AM) I think it's a great idea. I used to put it in the suggestion box about every version, but lately it slipped off my radar. I would also suggest built-in lables for Sequence-Locals. (Not that I would ever use a Sequence Local!) It seems obvious to me. NI pushes for programming standards, including good documentation, but this obvious feature remains missing. Cheers, Dave T.

There have been a few threads about using VMWare to test LV programs on different OS's and to keep different versions of LV separated. I used it briefly to try and test LV 8.5 beta. It worked, more or less, but the performance was less than ideal and I eventually gave up on it. I was wondering if anyone had tried usingn MS Virtual PC 2007? From what I've read, Virtual PC 2004 was slower than VMWare, since it didn't have some of the tools VMWare did for optimizing graphics and hardware access. Hopefully it has caught up by now. Any opinions/experience with this? Thanks, Dave T.

Thanks for all the suggestions. I also found a website that gave a really easy explanation: http://www.maths.surrey.ac.uk/explore/emma...es/Vector7.html Based on that, I created a VI to do this. It is posted on my website if anyone else should need it: www.originalcode.com, under Programs, then Scientific Programs. Cheers, Dave

Mike, Thanks for the suggestion. I'm having a bit of a time interpreting it, though, for two reasons. Perhaps my description wasn't detailed enough. I intended to imply that phi and theta were the azimuth and elevation in three dimensions. So my first problem is that your description seems to apply to two dimensions. My fault, since I wasn't explicit enough. Secondly, though, I don't understand, even in two dimensions, how sin(phi1) = y1/phi1. I think sin(phi)=y1/R. Since we're just talking angles and directions, you could assume unit vectors, R=1, and calculate y1 and y2 based on phi1 and phi2, but I think that would just be sin(phi1) and sin(phi2), without the additional factor of phi1 and phi2. I think one could approach the 3D problem by rotating the coordinate system so that the two lines are in a plane, then using your approach. There are other approaches as well. But I was just wondering if anyone had already packaged them up. Regards, Dave T.

Hi, I was wondering if anyone had developed a VI for calculating the angle between to arbitrary lines which both pass through the origin. E.g., given phi1, theta1, phi2, theta2, find the angle between the two vectors. I've found some descriptions on the web. It doesn't appear entirely trivial, but not all that difficult either. But if someone has already done it, it would be nice to have that as a starting point. Thanks, Dave T.

Another quick update - Bringing this issue up with NI resulted in the assurance that it was on their radar and that improvements were being made. Let's hope that this gets better in the next release... Dave T.

QUOTE(Michael_Aivaliotis @ Oct 4 2007, 09:17 PM) The VMWare idea is a good one, though I've been frustrated with the performance of running under VMWare. I realize you are just talking about doing the builds there, but it seems like a somewhat laborious process to create an installation with all the right drivers for each build. Given the current situation, it might be the best solution. Shouldn't be necessary, though. Also, just a quick update on my recent situation. As per Michael's suggestion (echo'ed by a helpful NI engineer), I did an uninstall and reinstall and then the build. It seems to have worked (though the build took forever...) That's the good news. The bad was anticipated in Michael's caveat: Since I was using DAQmx and VISA, and due to the multitude of dependencies, I had to uninstall almost every NI driver on my machine. When I got done with that, I found that it had partially uninstalled LV 8.2! The directory was still there, but the desktop shortcut wouldn't launch it. Double-clicking on the LabVIEW.exe file brought up a dialog saying that it wasn't activated. (I didn't push it any further, just bailed and reinstalled LV.) Anyway, after some grief, it looks like all is working, but there just has to be a better way... One last issue - my installation turned out to be 706 MB, and my CD only holds 702!!!!! Cheers, Dave T.

QUOTE(Michael_Aivaliotis @ Oct 4 2007, 09:03 AM) Michael, Thanks for the reply. Just to verify, before I go messing up my entire installation of NI software: Your recommendation is to insert the newest, latest, greatest 3 CD set of NI drivers, upgrade everything on the computer doing the build, then re-run the build and it will ask you for those same CD's? Sounds like it should work... I agree that this is a major pain, and could really use some improvement. Thanks again, Dave

QUOTE(Michael_Aivaliotis @ May 16 2007, 12:01 AM) I just ran into this problem with a slight twist. Last night I tried making an installer and including some drivers. It started up, then asked for the Aug 06 Drivers CD 2. After searching through a half-dozen CD cases of NI disks, I found the Aug 2006 Dev Suite set and put in disk 2 of the Drivers. It still wouldn't take it!m After doing multiple installations and uninstalls, betas and what-not, I can't say for sure that the CD I tried was the exact one that was used to install some particular driver, but the label on the CD sure seemed to match. There's got to be a better way. Perhaps there should be an option for caching the installation CDs on your hard disk right when you install them. Might require a sizeable chunk of hard disk, but that isn't such a problem these days. At least those of us who develop with multiple versions could plan for this. Any other progress on this issue? Regards, Dave T.

Brian, Buddy Haun, an Alliance member here in Colorado, and I discussed our similar efforts to solve these types of situations some time ago. He developed some interesting techniques for dealing with this that go beyond what I have done. You should be able to find an e-mail address for him through the Alliance list on ni.com. The basic idea is to use a hierarchy of type-defs. Use one non-strict type-def to define the type of your data. Then make several strict type-defs that each use the non-strict type-def within them. Each of these strict type defs can have a different appearance. When you alter the root type-def, you'll need to update all your strict type-defs, but those will be the only edits. All the instances in all your VI's will then be updated as you desire. Using this technique, you can display the same data cluster in multiple places, but hide certain elements from the user depending on the context. Cheers, Dave T.

George, How about making an enum with all the names, and a matching array of values. On your block diagram, drop enum constants and set them to show the name of the item you want, then use that to index the array of values. It depends on how you are using the names. If you need to have strings for names, then it gets awkward, since you would need to match the string to either an array of strings or the string array of the above-mentioned enum. To get a bit obscure, I wonder if you couldn't make a polymorphic VI and use the click-able name below the VI Icon to choose an instance, each instance being a different constant. It would label the block diagram object with the name of the constant you are using, and it would condense everything into a single icon, rather than having a name index and array. There are probably other clever ways of packaging up, too... Dave QUOTE(george seifert @ May 15 2007, 07:38 AM)

EJW, As others have said, it is all relative - relative to your signal frequencies, your hardware capabilities, and your cpu speed (as well as other factors). Just talking aobut data acquisition would be a difficult enough conversation, but to include computation, analysis, and display really makes it a large can of worms. Nonetheless, I'll throw out a couple of benchmarks for reference. One project I did uses a 4-channel 6115 sampling all four channels at 5 MS/s. It streams 20MS/s (40 MB/s) into memory scans the data for events, pulls out valid events, saves them to disk, and does a minimal amuont of display. If there is a relatively low frequency of "events", this system can keep up with all of that and not miss any data. If the event rate goes up, the duty cycle goes down and it misses data. This is on a fairly recent PXI controller using the PCI bus for data transfer. In this case, 5 MS/s is pretty fast data acquisition, since at high event rates, both the CPU and the disk can be maxed out. On another system, we have 4 channels of data acquired at 500 MS/s. It has similarly random events, but typically at a lower rate. This runs on a much older computer (500MHz PIII). Although the raw data acquisition rate is 100 times faster, the CPU is usually not taxed very heavily. (Under high event rates, this system can max out the hard disk and begin loading the CPU, but those conditions are fairly rare.) If someone asked me if 5 MS/s and 500 MS/s were "hgih speed data acquisition", I would almost always say yes to the second, but the first would require more context. Regards, Dave T

>The good ol 7805 is a robust 5V regulator. Heres a link for a sample circuit. The 7805 is simple to use and a great solution for many situations. Keep in mind the efficiency, though. Running a 7805 off 12 volts means you'll get less than 40% efficiency, so for each Watt of 5V power you use, you'll be putting 1.5 Watts of heat into your system. A DC-DC converter, on the other hand, can be found with at least 80% efficiency, so the same 1 Watt of 5V power would only dump 250mW of waste heat. Since you mentioned that it is a low power system and you were concerned about efficiency, I thought it might be worth pointing out. Dave T