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Thread: "60,000 PPS max"?

  1. #11
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    Again, i dont undertsand why you guys are talking about quality. I want to know if running a 30k scanner at 40k or 40k at 60k in your program will actually do any damage, because it seems some noticeable people might have been doing that for a while.
    Ok, lets go back to the start.

    Yes, you can run a scanner faster than 30k.

    How fast you can run it safely depends on the angle you are using and the complexity of the pattern.

    Tuning for 8deg at 30k using the ILDA test frame is a fairly good way of finding out if your scan set will handle larger angles projecting typical beam patterns.

    You probably won't get good graphics at those angles.

    So in answer to your question, I'll ask you another question...

    Tell us what you want to project at 40 or 60k, and how large, and I'll give you a reasonable estimation of whether it'll be damaging. Unfortunately, you cannot simply home in on one parameter like you're trying to do, as they all influence each other.

    So quality is relevent, because it is also an indication that the scanner is running outside of its comfort zone, and therefore closer to the point of being damaged.
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  2. #12
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    Quote Originally Posted by dream View Post
    Again, i dont undertsand why you guys are talking about quality. I want to know if running a 30k scanner at 40k or 40k at 60k in your program will actually do any damage, because it seems some noticeable people might have been doing that for a while.
    As others have said, it depends on what you are scanning. No, you cannot break your scanners running them at 40K if you are not running a huge angle or an intense pattern/graphic or both. Even though you can scan at 40K, these scanners can get hot, really hot. DT40s also use conventional bearings and as the heat goes up, the oil in the bearings becomes less viscous and will leak out more than normal. The extra heat also plays havoc with the coils and they may start to come apart.

    Can you run anything at max? Sure. Is it a good idea to? No.
    Those who fail to grasp art are the ones who criticize it.

  3. #13
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    Quote Originally Posted by absolom7691 View Post
    As others have said, it depends on what you are scanning. No, you cannot break your scanners running them at 40K if you are not running a huge angle or an intense pattern/graphic or both. Even though you can scan at 40K, these scanners can get hot, really hot. DT40s also use conventional bearings and as the heat goes up, the oil in the bearings becomes less viscous and will leak out more than normal. The extra heat also plays havoc with the coils and they may start to come apart.

    Can you run anything at max? Sure. Is it a good idea to? No.
    Nice. Your avatar maybe needs changing, it's nice to see people giving a damn, correcting stuff when people ask questions at the same time the answers are flying around several other threads at once. When I saw this thread earlier I felt like dropping the H-bomb. (as in House-bomb, maybe I should restore my original avatar here...), but to be fair, the guy IS asking, which is better than not asking. Another funny is JohnYayas' sig. I think that's a tad bit out of date by now.

    Re 506, given the resurgence of abstract generators, which mostly use waveforms that don't force the scanners into large signal (ballistic) responses until the angles get really wide (assuming the generator's square wave is bandwidth limited, anyway), then the 506 scanners are especially appropriate for abstract generators because they'll make better wide angle use of signals that tend to stay in small step response behaviour than any other scanner. The Widemoves had a rep for indestructibility, but the 506 should likely combine that with far better accuracy. I have no idea how DT40's will handle this but I did watch Bill's latest video (two nights ago I think) and it looks like they won't do nearly so well. Graphics with lots of curvature might not show their weaknesses, but the geometrical forms of abstract generation definitely will.

    In the simplest possible reduction, what my post should mean to the original poster is: speed isn't everything, to the point where if these other details are poorly designed and handled, even speed won't save a scanner from looking bad. Probably just make it look worse the moment you try to make the image big enough to be useful.

  4. #14
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    Quote Originally Posted by dream View Post
    Again, i dont undertsand why you guys are talking about quality. I want to know if running a 30k scanner at 40k or 40k at 60k in your program will actually do any damage, because it seems some noticeable people might have been doing that for a while.
    Short answer, Yes it WILL damage! Anyone who fails to grasp the notions that make up the 'quality' will almost certainly fail to understand how far the angle can be pushed wider until the scanner coils burn out, or the magnet (likely NdFeB (neodymium based)) gets so hot it becomes demagnetised, or the bearings seize up perhaps even before all the oil is driven out of them by the extremity of heat and motion.

    Even if you understand all that and are cautious every inch of the way, the scanners will still have a much shorter useful life. Just because someone is 'doing it' doesn't mean they'll do it well enough or long enough. They don't have to if all they care about is selling scanners to people who don't understand this risk of early failure. It's the same with diodes. Again and again people discover the risk of overdriving stuff to early death is real, warn others, and again and again there will be someone who asks as if none of it ever happened before. So just start out assuming that stuff HAS happened before, and search for people taking about it. As this happens a LOT on PhotonLexicon it's a very easy search!

  5. #15
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    Quote Originally Posted by dream View Post
    Again, i dont undertsand why you guys are talking about quality.
    Because all scanners are not the same.

    It's not just about damage.

    Compare graphics or beams from DT40's and Cambridge Scanners side by side at 30K and I'll guarantee the ones on the Cambridge will look "nicer" (well at least they did for me).

    I've seen a beam projector swapped from DT's to Cambridge and the delineation between the colours in discrete fans and beams was much cleaner almost certainly due to the greater accuracy.

    ...and this is the reason - because scanners are not just about speed but accuracy. If you watch the Scannermax videos then you'll see that one consequence of increasing speed on most scanners is that you start to get resonance which results in straight lines no longer being straight but wavy as the mirrors start to resonate beyond certain speeds. You also get rounded corners because the scanner is travelling so fast that it cannot stop to turn a sharp corner thus giving a right angle, but instead to get round it has to cut the corner, giving a curve. There are other affects as well.

    The result is that as speed increases beyond 30K, the quality of the graphics or beams suffers as well. For beams, Joe Average will never notice the difference unless he sees another projector with more capable scanners in it, such as the Cambridge, or unless you really push the scanners way beyond their limits. With graphics the "mistakes" will be far easier to spot.

    Also, speed isn't everything from a brightness POV. I'm sure Norty and X-Laser will tell you beams appear brighter at 20K than 30K due to the longer dwell times.

    Finally, the new Pangolin scanners 506's and the as yet unseen ScannerMax, re-write the rules because they are offering much greater accuracy than has been seen before at much wider angles (or faster speeds), and this offers the end user the opportunity to obtain a much better projection image for less cost (at least in the case of the 506's - we don't know the ScannerMax pricing yet).

    I hope that helps.

  6. #16
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    Also, speed isn't everything from a brightness POV. I'm sure Norty and X-Laser will tell you beams appear brighter at 20K than 30K due to the longer dwell times.
    Agreed, although I'd made the assumption that any fixation with speed was due to wanting to display complex graphics with the least possible flicker, and so ignored the fact a lot of people doing beams reduce speed for the width and (subjective) brightness benefits.
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  7. #17
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    But that is what I've asked in this thread.
    There's no need to give all that info about how the graphics quality or the brightness is affected by the kpps, because I haven't asked that. Obviously I've tested myDT40s at 60kpps before posting here, I know how the graphics look. of course when some explain that loss of graphical quality is important because it signals danger that's another thing.

    I'll say why I want to run them at 60K in my program LSX. Because a 500-800 point stock animations at 8 degrees gives a lot of flickering, changing the scanner speed from 40K to 60K eliminate the flickering with no loss in quality.
    Why I get so much flickering with 800 or even 500 points on a DT40 I still haven't managed to figure out. Some say flickering is expected, others say they are surprised and don't know the cause...
    It may have been useful to provide that information in your initial post, so that we had some context to the question.

    If you'd have said 'I'm running 8 degrees, stock animations and they smooth out at 60k, am I going to damage them?' you'd have got the concise answer you're looking for.

    Out of interest, what is the quality like at 60k/8 degrees?

    Incidentally, check out page 10 (iirc) of the ScannerMax 506 review, Steve MixedGas posted a little snippet from the ILDA standards that talks about 'why' 30k is the standard for tuning, but doesn't necessarilly mean you have to run at that speed.
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    I thought it fitting, considering the rocky terrain.

  8. #18
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    Personally I think you're asking about the same thing in different ways, but they're all related to the same issue.
    Starting 3 threads about fundamentally the same thing is only going dilute your answers, if people can even be bothered to reply to all of them.
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  9. #19
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    Quote Originally Posted by norty303 View Post
    Personally I think you're asking about the same thing in different ways, but they're all related to the same issue.
    Starting 3 threads about fundamentally the same thing is only going dilute your answers, if people can even be bothered to reply to all of them.
    Also, I specifically mentioned damage because when people won't accept the real limits on scanners they WILL push to the point of damage. And just as such points are ignored (yet again here in this thread too), they will blame some other event, never the one they cause, just because they do not see 'instant rough justice' kick their arse for doing it. Looking for one simple answer won't work, any more than looking for one simple cause for obesity. There's a whole chain of things, some we can control, some we can't. So the only handle on this is the stuff we can control, we can at least balance probability in our favour that way. Ignoring this and chastising those who do not talk of actual damage while ignoring those who do, is a terrible way to start dealing with the problem.

    It's time people did deal with it because this argument has been raging for a decade, and is boring. For an industry that prides itself as being on the cutting edge, this is a very counter-productive thing to happen. To get good performance cheap relies on bulk production of a high standard device. Pangolin getting to the point where some big firm commissions research and production of half a million scanners is the first big breakthrough in that decade. This is like the day that people accepted that the world was not flat, despite sailors and cliff-dwellers telling them it wasn't for years. You'd think that eventually the old, silly arguments would cease. Both 'sides' like to talk up their angle, but Bill's given technical details and hints (like resonance of cantilevered beams) and other things we can all check out independently. When someone claims to have done a thing better, faster, it ALWAYS needs context to define it. Any look at the web-page specs for most scanners shows no context at all. By now people should be wising up to the fact that this is NOT a blank cheque to suspend disbelief like in a movie. These details that some people want so desparately to ignore are the ones that will continue to annoy them because they won't go away. Better to at least try to get to grips with it. A bit at a time, doesn't have to be at once. Anything beats standing still, pissing into the wind while other people discover a new and better way to go.

  10. #20
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    On the subject of getting best speed, one way to find out what will work safely for a usefully long time is to rotate that LaserMedia test pattern (switching off any interpolation the software might be adding), and running at 30K, widening the scan angle until the diagonals in the pattern begin to bow apart. Then cut scan angle right back to a small point, increase speed to 40K, 60K, whatever, without retuning the scanners, then increase the scan angle as before, looking for that bowing effect again. The ratio of scan angles at which bowing occurs will likely be a useful guide as to what you can get away with for higher speeds.

    As far as I know, a scanner like the 506 that can do wider angles at 30K because it stays with good small step response at wider angles than most if not all other scanners, may also allow wider angles at higher speeds than most other 30K scanners when run at the new speed, but I think Bill said that this is not a directly useful relation, and that the 506 will not do so well at high speeds just because the small step response is good at wide angles at rated speed. Whatever they will do, I think looking for the point where the small step response gives way to ballistic response with increased scan angle at high speed is a safe way to test. There will likely be an audible change in the sound the scanners make too, so use sight and sound to guide you.

    I'm not sure about most scanners sound, but I noticed that the Widemoves would always have a clean, low sound if most of their drawn pattern was in small step responses. If anyone can add some decriptions of how sound changes in their scanners at high speed, it might be useful. Obviously not audible in a loud show, but it will be during tests beforehand...

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