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Thread: Pangolin , comes up trumps again !

  1. #21
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    Exactly Norty.

    Which was my point, as the question seemed like a bit of trolling...

    James
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  2. #22
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    Quote Originally Posted by Laser Electronics Ltd View Post
    I'm curious about the safety aspect when the laptops crashed.
    The Fb3 cards will project the last image in memory if the supply voltage is present from the USB port.
    If something with a frame buffer crashed, the expected behavour would be that the existing frame iterates in the absence of any other influence. That would be the best default behaviour, not the worst, because being trusted to handle that framed data is the main purpose of having a frame buffer at all. If people need dedicated failsafe beam blocks, they need fast-reacting hardware methods with a way to sense a bad condition. The worst anyone could accuse the FB3 of, assuming such a charge is even valid, is not having some output terminal explicitly intended to indicate that the frame buffer cannot be altered from its current state. I have no knowledge of FB3 details, but there is a 'division of labour' issue here that isn't hard to grasp.

  3. #23
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    Hi Folks,

    I don't typically get to PL to participate in conversation, but a Pangolin client pointed this post to me, so I figured I'd give my response. In the same light, I do not monitor responses to my comments either. Multiple people on the Pangolin team do routinely monitor the Pangolin forum, and if you'd like further information or to continue the discussion, you'll get more lively responsiveness by posting there.


    Quote Originally Posted by Laser Electronics Ltd View Post
    I'm curious about the safety aspect when the laptops crashed.
    The Fb3 cards will project the last image in memory if the supply voltage is present from the USB port.
    Whitelight had it correct. No FB3 ever made has a "frame buffer" of any kind. When fed by USB we use what we call a "direct feed" approach. With this approach, the FB3 is literally fed every single point and outputs every single point. The FB3 also has smarts enough that if the feed of points stops, it will center the beam and extinguish all laser power.

    The FB3 also has other safety-related features that, so far, I haven't seen in other people's hardware. There are some Chinese projectors that require a super-low-impedance input signal in order to trigger the external ILDA interface as opposed to using a built-in pattern generator. With other laser controllers (including the QM2000 by the way, which is older) if you connect the controller hardware to these Chinese projectors but don't apply power to the laser controller hardware (or for example if the computer is turned off), it will sometimes put the projector into a kind of nether-state, where the scanning stops, but the beam is on, fed by the pattern generator. If you try this with the FB3, you'll find that, even when it is not plugged into USB for power, all scanning and laser output will stop. We've built this same technology into our FB4 and will be building it into all future hardware we make.

    Quote Originally Posted by JStewart View Post
    With respect, if you are relying on software operation as part of your safety case, you are doing laser safety wrong...

    The risk assessment should identify a software/computer failure as being a reasonably foreseeable fault, therefore other controls (precautions) would be needed to ensure the safety of those that could be exposed.

    James
    Correct. Completely setting software failure aside, there is also laser controller failure (for example, failure of a power supply component that is not critical for the processor-portion to operate but is critical for the output section to operate) that may cause an unsafe condition. Likewise, user error (for example setting up target mirrors while others are present in the room) is likely by far the most likely point of "failure". The projector itself, as well as other control measures should defend against all of these kinds of failures, and more...

    Quote Originally Posted by The_Doctor View Post
    If something with a frame buffer crashed, the expected behavour would be that the existing frame iterates in the absence of any other influence. That would be the best default behaviour, not the worst
    Hehe. Doc, your statement above makes the broad assumption that what was being scanned was safe in the first place. What if "the frame in the buffer" was substantially a single point? This is of course potentially a VERY UNSAFE condition! Completely setting aside whether such a beam goes into the audience, it could actually start a fire under an unlucky collection of circumstances...

    Folks, this is one of the reasons why scan-fail safeguards and probably divergence increasing means should be used in all cases.

    Best regards,

    William Benner

    PS: Thanks for the complement Laser Mad! I think a lot of people could say the same thing, but everyone is so busy, that few people stop to say thanks for anything these days.

    By the way, while *I* am thinking about it, I'd like to say A BIG THANKS to Robert Evan Teet for coming up with the idea of Photon Lexicon and for continuing it to this very day!

    Quote Originally Posted by Lasermad View Post


    WHATS THE LONGEST A PANGOLIN CARD HAS BEEN RUNNING WITHOUT FAIL ? out of intrest ?
    The original QM2000 made in 1999 is still operational in my PC and used every day. And we have many clients who are still using the QM32 board and even a few on the old Amiga platform. We build everything to last forever. Same thing we're doing with scanners by the way...
    Last edited by Pangolin; 08-29-2013 at 09:40. Reason: Added Thanks for Laser Mad

  4. #24
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    Quote Originally Posted by Pangolin View Post
    Hehe. Doc, your statement above makes the broad assumption that what was being scanned was safe in the first place. What if "the frame in the buffer" was substantially a single point? This is of course potentially a VERY UNSAFE condition! Completely setting aside whether such a beam goes into the audience, it could actually start a fire under an unlucky collection of circumstances...

    Folks, this is one of the reasons why scan-fail safeguards and probably divergence increasing means should be used in all cases.
    Exactly so. What I was getting at is, 'garbage in, garbage out'. If a frame buffer has an unsafe pattern in it, it doesn't know one way or the other. So the only thing a frame buffer system can do is alert some other system to the loss of external control on its own content. How it does this I don't know, depends how it's made. But a hardware buffer system can probably know when it's not getting changing input anymore. Could just set a flag for the safety hardware to detect. Then all the software controller has to do is update the buffer occasionally even if the content is fixed, just to keep it from assuming that control is lost.

    I think we agree on not placing the burden of safety on the buffering system... The guy I was answering seemed to think he should.

  5. #25
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    Quote Originally Posted by Pangolin View Post
    The original QM2000 made in 1999 is still operational in my PC and used every day. And we have many clients who are still using the QM32 board and even a few on the old Amiga platform. We build everything to last forever. Same thing we're doing with scanners by the way...
    Nice. In the Snowflake-thread there's talk of a QM board being 'roasted and toasted'. I'm still wondering how that could even happen. Nothing lasts forever, even diamonds, but some of that talk seemed to imply a QM board had the shelf-life of a tomato. Joking, but even so, they don't just 'wear out' naturally over the course of general use in a few years. Makes me wonder what kind of a life they sometimes get.

  6. #26
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    Quote Originally Posted by The_Doctor View Post
    Nice. In the Snowflake-thread there's talk of a QM board being 'roasted and toasted'. I'm still wondering how that could even happen. Nothing lasts forever, even diamonds, but some of that talk seemed to imply a QM board had the shelf-life of a tomato. Joking, but even so, they don't just 'wear out' naturally over the course of general use in a few years. Makes me wonder what kind of a life they sometimes get.
    Roasted and Toasted happens when you abuse them:

    I have two 1996ish QM32s that still run, far outliving the succession of ISA bus machines they have lived in. Even with a blown color channel GAL chip, the one still outputs XY and Blanking, making it still useful. They are through hole, and thus quite repairable. The license part still works as well, so I can load up old LD and still edit and run. The hardest part is finding ISA Bus machines with a full length slot to support them.

    While I don't suggest it, I've seen QMs in night clubs drive shorted analog lines for days.

    Tough beasts.

    Steve
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  7. #27
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    I still have an Atari 2600 that is still alive and kicking. Stands to reason that if properly built, Pango cards should last a very long time. In regards to the Snowflake thread, I think he is going to learn a valuable lesson on why honesty is always the best policy.
    If you're the smartest person in the room, then you're in the wrong room.

  8. #28
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    hardest issue is keeping the outdoor camera online , the SMS control of power is useful
    but signal can be flaky sometimes

    I aint found an outdoor camera yet that takes a sim card , and can reset itself to keep itself online 24/7 9 If you know of one please point it out ?

    currently using router with 3G dongle attached , camera plugs into that , them camera power and router can be switched
    off via SMS power relay , to enable restart if router or dongle or camera connection hangs , this works but its fiddly


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    thought you might enjoy the sexy wiring :-) (( Tony is likely having heart attack ))

    security camera housing contains ......... laser :-) controlled by laptop with 3G dongle and logmein and a VERY RELIABLE FB3 !!!
    Last edited by Lasermad; 11-25-2014 at 21:58.
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  9. #29
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    Hi
    Your original post was over a year and a half ago. Are you saying this stuff has been in operation all this time? If the plan was for it to be, I am some what surprised you elected to use laptops and not small server level PCs, as laptops are not designed to run 24/7 where servers are. What kind of environment is this stuff in and what cooling if any is employed?

    And what's it all for?
    Cheers

    Colin.

    Anyone wanting to be a politician, should automatically be excluded from being one!

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