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David Boyd

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David Boyd last won the day on April 22 2013

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About David Boyd

  • Birthday 03/17/1958

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    Atlanta, GA USA

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    LabVIEW 2018
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  1. Reading twenty-plus-year old articles like that really starts to make me feel ancient. I was about to reply with the obligatory grumble about preferred-case spelling ("it's LabVIEW!"), and instead looked up the author. Found out he passed away just before MacWorld Expo 2007. Thanks for locating and posting this. Dave
  2. I still have my "Power to Make It Simple" tee shirt that I "won" at the end of my three-day Basics I class (I think it was fall of '97... does that seem right?). The black is pretty faded. I was excited to upgrade from 4.1 and try out the miraculous "undo". And real multithreading (under NT 4.0)...
  3. Thanks, @hooovahh, for pointing me to those older discussions, which I probably totally missed. @drjdpowell's comment about a clone's reference having guaranteed validity when passed to its subVIs doesn't seem to apply to my/@Neil Pate's use case - we're sending a cloneVI ref to another VI via messaging. So no telling when the original VI ref might go out of scope. And I just realized that my demo code for launching off clones (and then later gathering their refs for subpanel use), explicitly closes the original VI ref after they're launched. There is still a static ref on the caller's BD though - I think there has to be since you need a strictly typed ref to make the ACBR work at all. My demo code is below. Dave
  4. I was browsing through class code from the Actor Framework (ashamed to say I haven't used this framework, yet, but that's changing), and stumbled across what appears to be a dire warning. (See the attached, or if you'd rather, read the BD comment here.) I've used an architecture for years now where I launch N clones of a VI using the ACBR in fire-and-forget mode, and subsequently the clones get a VIref to themselves and register that (with an assigned index) by message back to a GUI VI. The GUI then allows the user to switch through the clones' FPs to be shown in a subpanel. I've never had an issue traceable to this. Note that in my code, the clone refnums are NOT obtained by an Open VI ref with clone name string (as shown) - they are implicitly obtained within the clones via a VI class property node. Does this warning imply that this architecture is somehow unsafe? I'm hearing AQ's authorship in my head when I read this warning. @Aristos Queue, are you listening? Can you comment? (Apart from chastisement for my only now learning about the AF - sorry.) Dave
  5. I might have a tactical advantage there... who would bother to load up on old LabVIEW versions just to look at my rookie LV4.0 code. (Now, where's that chart Scott Hannahs did that shows the last version that'll open 4.0...?) Actually, I have plenty of much newer code I'm ashamed of, so who am I kidding?
  6. I spent a little time this afternoon searching Info-LabVIEW ca. 2002, and you're absolutely right, there WAS a lot of confusion back then about how to apply the "new" paradigm effectively. IMO, more than any other feature added since I started using LabVIEW (4.0/4.1), the ES really reset the way I thought about LV programming architectures. There's good lengthy discussion pertaining to the ES in those Info-LV archives, BTW, especially a few excellent posts by Greg McKaskle describing how they made the design decisions the way they did. I'd recommend looking back through that material to anyone following this thread. Dave
  7. OK, having heard from all my multiple-ES LAVA colleagues, I'm seriously in need of a reality check. AQ: do you recall any early caveats from NI (either in release notes, or help, tutorials, online discussion, etc.) that warned against the practice? I'm vaguely recalling there was an issue with the way ESes invoked some behind-the-scenes setup as soon as the VI was loaded into memory, well before user code started executing. Or maybe I was living in some alternate reality back in the 6.1 days? Dave
  8. Somewhere in the dawn of the ES (6.1? I think), while wrapping my head around this great new paradigm, I took it as a commandment that THOU SHALT HAVE NO MORE THAN ONE EVENT STRUCTURE PER DIAGRAM. I've frequently been appalled by the code of some of my coworkers who blithely put down 2, 3, or 4 ESes in separate loops. (Heck, I don't even like to have more than one ES in an entire execution hierarchy, maybe I'm carrying it too far?.) So it wouldn't bother me. But I am curious, AQ, if you went ahead with this enforced limitation, what kind of upgrade mutation could possibly save such (IMHO, barely maintainable) code that's out there? Dave
  9. I've used Digi devices for years, with few issues. Biggest system to date has four Etherlite 160's (total of 64 ports); sixty ports are tied to UUTs spewing 6400 char/sec each, all of which is digested by my LabVIEW application. The other four ports are used for instrumentation, doing query/response (a few dozen chars per message, as fast as the instrument responds). These terminal servers are setup to use the Digi RealPort driver, which provides standard Windows comm API, so VISA treats them like local asynch serial. When you get up to this level of activity, with array-launched VI clones, and lots of queue/notifier/event structure support, you have to be pretty careful about the details. Seemingly minor changes to cloned code, reentrancy settings, execution system assignment, etc can mean the difference between a working app and a quivering heap of unresponsive code. Dave
  10. Thanks, Crystal. As one of the "Old Guard", you already (IMO) have a credential that surpasses anything a CLD certifies. Funny, though, perhaps we're not as tightly regulated as you, but we've never given a second thought here to migrating to newer releases when starting fresh projects. Sometimes I think we are still flying a bit under the radar. We focus more on qualification of test systems, rather than V&V of our LabVIEW-developed code apart from those systems. If we were to do more formal software verification, we'd surely need to add personnel to handle that workload. Anyway, I took the test today. Got an 85. Way lower than my previous CLD-Rs and the original CLD. Not proud, not pleased, just relieved. But I still feel as though too much of the test was of the form: 13) Which of the following (blah, blah,...)? A. A twisty little maze of passages, all alike B. A maze of little twisty passages, all alike C. A twisty maze of little passages, all different D. A maze of twisting little passages, all different (With a nod to Colossal Cave, Zork, etc.) Dave
  11. I'm scheduled to take my CLD recert exam on Monday afternoon; this will be my third recert (took the CLD in Austin during NI Week 2004). As my LAVA listing shows, I've been using LabVIEW continuously for nearly thirteen years. I consider myself a pretty sharp guy (LV-wise), with a background in automated test, and the programming (in various environments) that goes with it, since the early eighties. My current employer didn't ask me to attain certification, I just did it on a lark. I forget the specific scores, but I know that the original CLD and two subsequent CLD-R's were all scored in the high 90s (I think one recert was a 100%). So I waited until today (Sunday afternoon, quiet around the house) to work through the practice exam. Ouch! Not a very pleasant experience, and when I scored it, not surprisingly, I barely scraped a pass. Random thoughts: I expect that with each passing recert, there will be a few questions added in that will demonstrate that I haven't adopted a new feature in my own development. And I know this has been discussed elsewhere on the forums. I'm OK with not knowing every new feature intimately. (Network Shared Variables; just haven't needed 'em, though I remember when they were DataSockets, before they grew up. Feedback nodes still confuse me with their syntax, I so prefer shift registers. And sorry Stephen, but I just haven't found a programming challenge yet that whispers "LVOOP, LVOOP" in my ear. Someday I'm sure I will make the leap.) Some of the example code snippets seem SO convoluted in their purpose, I can't help but wonder - am I being evaluated on how well I can troubleshoot some newbie-LV-minion's code? (I don't have any newbie-LV-minions at my command at my place of work, for better or worse.) Guess I'll read some of the dustier corners of the online LV help on Monday, if I can spare the time. Wish me luck, never thought I'd need it. Dave
  12. Is Windows server 2003 a supported target for LabVIEW 2009? I know that it specifically WAS NOT under prior versions, though over the years there have been reports of folks running LV apps on WS2003. I'm just asking to point out that you may not be able to get support from NI for any issues you have. Whether this is an issue for you, I couldn't say. Along other lines, have you checked the Windows event log on the target? Perhaps there is an application error event getting recorded which could suggest what's going on. Good luck! Dave
  13. I've been bitten by my misunderstanding of custom scaling and min/max definitions too. Classic example: I have a 0-15psi pressure transmitter that's 4-20mA current loop. I create a custom scale thusly: prescaled units in Amps scaled units in psi slope 937.5 intercept (-3.75) I specify this custom scale while defining a virtual channel that uses an NI current input, and am tempted to specify the channel min and max as 0-15 psi. Bad choice on my part! While trying to perform a software cal on a sensor, if the raw current reading is 3.7ma, the scaled value is pinned to zero psi even before I apply software correction factors. Perhaps this isn't really particular to the custom scaling, but I would still somehow expect the scaled channel to return all values within the chosen range of the underlying hardware. Having the max and min values specified in terms of the scaled value is just confusing here - what I SHOULD have done was to specify (-3.75psi) as the min value and (+16.41psi) as the max since the hardware will choose an input range that can actually report (0ma) to (+21.5ma). If I DON'T do this, and go with my original impulse, my scaled readings will never appear outside their valid ranges even if the hardware disconnects (goes to 0ma) or otherwise "goes south". Dave
  14. QUOTE (LV_FPGA_SE @ Jan 21 2009, 08:02 PM) Geez, Christian, that was priceless. So simple an idea, it just took one clever person to conceive of it and create the website.I didn't piss myself, but I narrowly avoided blowing coffee across my laptop keyboard. Thanks for this. Dave
  15. QUOTE (Michael_Aivaliotis @ Nov 17 2008, 02:58 PM) Any updates, Michael? Just wondering. Wasn't there an issue in the past with some key from Google that went invalid with a server move/domain change? Dave
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