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Thread: Safety-concern with the "Shutter" on LS-Pluto IIs / Venus... and a DIY solution...

  1. #1
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    Lightbulb Safety-concern with the "Shutter" on LS-Pluto IIs / Venus... and a DIY solution...

    Hey Kats -

    ..So, been helping one of our latest 'Laser-Pups' / LJ-Star of Club-SELEM Knight AnthonyGarcia with his acquisition / importation of a Pluto II from Lightspace, while we work on getting his Variance done / pushed-thru / safety / Op-training, etc, etc.. And, in so-doing, I've had the chance to pour-over the Pj-line / design, and features. This is the 'latest / greatest' version of the Pluto - with the touchscreen CP, on the back, etc - so, I don't know if previous versions have this same "shutter", but I'd presume so, and, regardless, this post / 411 applies to *any* of the Pj-lines, newer (ie: Venus..) or older-models, etc, that use this same component..

    ..As the thread-title states, the 'issue' I discovered / have, is with the "shutter" - AS they ship these units, the shutter is actually a *stepper-motor*, that is 'driven' to both open and close.. Here's the component: (..and it was 'pulled up-top' to show it clearer / stage for the vid-clip..)

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ID:	44616 ..And, here's a vid-clip:

    ..This is *WAAAY* TOO SLOW, to be an effective part of any 'E-Stop' / Safety-device chain.. Regardless of if you use the keysw / Interlock-plug, Optical-deck cover-plate Interlock (kudos, btw.. or, just flat out shut off the power (via the toggle-sw or just 'pulling the plug'..) The 'response time' for closure of the shutter / blade is *WAY* too-slow. It should at least approach 'blink-reflex' time (0.25 sec.) and the way it - currently - is controlled, it's several-times that..

    Disclaimer: This Pj was *not* purchased thru the 'Official US Distro' for these, which, as I understand, is Laser Rentals, Inc. (W. Meador) out of MO.... SO, I want to make it *clear* that this Pj - as it arrived / as-is the subject of this review / advisement, is NOT the 'Officlal' version as-Certified by their Co. / distro'd by them. This means, that the US-Certified version they-sell / ship, *may not* have this 'issue' (..and, very-likely does not, as I cannot imagine Walt passing these, as-is, since these are absolutely a non-compliant shutter, as-is...) Otherwise, the direct-sale imported Pj is 'reasonably-well compliant'.. Additionally, this Pj was Imported with an FDA 2877, under parts of Conditions C & D..
    ---

    ..But, some may counter, '...Ok, Gringo, but do you even *need* a 'hard-shutter', with digital (modulation) output control in solid-states, these days? I mean, if there's zero 'input' (..Or, you 'kill it'..) there's no Output! Why do I even need a stinking-shutter?! Aren't you just being a safety-nanny, again??..'

    ..Well, the answer is two fold: a) IF you live in the EU, or a Country where you're NOT subject to the CDRH's Regs / compliance-standards (..which do, indeed, *still* require a hard-shutter, even in 'solid-state' Pj's..), ie: those that live / Op where the ONLY standard is the 'IEC', well, then Yes, a hard-shutter is seen more as 'Optional', by the strict 'Letter of the Law'.. HOWEVER, even in such a case, using a proper hard-shutter is just best-practice, especially as you get into the higher Class IV power-ranges, as it gives the Projector a built-in 'backup' / CYA-mechanism..

    ...ie: What happens when there's a 'transient' voltage, kicked thru the system, ie: if the PC has to restart, with the PJ still connected, etc, and a *full power beam* is sent-out, thru the sys? IF there's NO shutter, well.. that beam may very-well knock someone - perhaps You - in the eye.. Doubt this happens? Then you've not been around very long.. I've seen even Kvants / RGBs and other 'hi-end' Pjs do this, under certain circumstances. And the 'Chijectors' - very often - some systems, nearly-always - do this, even on just shutting off / 'pulling' AC power (!) ..So, if you don't have a proper-shutter, or, in the case of this 'stepper', which takes like *2 seconds* to close (!!) THAT's a safety-concern, regardless of 'what the Regs are' / aren't..

    b) ..In the case of the 'Pluto', and many other systems that - attempt - to incorporate 'Scan Fail' protection, or the "Safety Circuit" as they call it - that doesn't work properly - (ie: You should NOT be able to just gently grab the scanner-mir, with nothing-being Input to the Pj - either from an External or Internal source - and GET it to 'spit out' a beam.. *that's* not 'scan fail', that's just FAIL... But, that's a topic for another thread, after some more investigation / research on what's being done / not-done properly, there..) POINT BEING, if you've, additionally, not-GOT a hard-shutter - with proper response time - then your entire 'Safety-chain' is broken, right out of the box, and having all the keyswitches / Interlocks / E-Stops in the world still does not make the Pj - actually safe - let alone truly 'compliant'...

    ..Now, I am in-touch with the OEM on this, and, I'm confident they will be willing to consider the wisdom of this observation / input.. Yes, it may end-up costing a tiny-bit more, but.. IMHO, it will be an improvement *well-worth* the Safety - and potential-Liability - risks, and a competitive advantage over other 'ChOEMs'.. But in the *meantime*, here's what I did / you can do, on a 'DIY level' to fix / better-this.. Introducing the Ledex Rotary-Solenoid:

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ID:	44607 ..and the Spec-sheet Click image for larger version. 

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ID:	44608 ..the one I picked / used is the H-2168-032, since it Ops off 12V (available in plenty (29A, iirc!) in the Pluto..) and has a really-low current-draw, so as not to 'unbalance the load' in the Power-train too-much.. And, the 'L-bracket' was one used in a dye-laser, but it just-so happened to be the *exact* beam-height.. (I'll take some pix / measurements / post-later, for those that want to fab-up something similar..) ..but, really, it's nothing fancy - just a piece of 1 1/2" alum. L-brackky, couple mount / shaft holes, and yer off.. piece o' cake for PL'ers..

    ..And, so-as to maintain the 'Pj-brain control' for the shutter (in-context of the safety-circuit..) we simply used a mini 5V-coil DC-relay, the Omron_G2VN-287P-US-DC5, and piggy-backing off the two OEM-stepper 'V-hi' lines (Yellow: +5V; Blue: GND) to gate it.. Here's how it all placed / mounted:

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ID:	44613 ..and here's the 'difference' / result..

    .....you pull the Interlock (either 'remote', on the rear, ILDA-sig, keysw or case-interlock)? BAM! That thing is closed in a snap... As it should-be / is the intention for the "shutter" as a component in the Safety-chain.. A 2-3 second 'railroad-crossing gate swing' is FAIL.

    ..Yes, of course, this Ledex is NO substitute for a Safe / spirit of the law / Regs-astute Operator, nor is it intended to fi a faulty Scan-fail system, nor can it prevent every-single instance of a 'transient V-spike' spitting out a full-power beam, etc, BUT.. In such cases.. after seeing the above two vid-clips.. Which pj would *You* rather be in front of, if there was unwanted Class IV laser-output, and the 'E-Stop' was tripped? I'd sure pick the Ledex!

    ..Anyhoo, again, this is not meant to be a 'Lightspace slam', etc.. Hopefully, this will a) inspire them to implement this *smart change*, even-if this is not for CDRH-Regs-governed customers - again: actual, real-world Safety ABOVE any / all 'Regs' - and / or, even if a 'true Ledex' is not used, but some other way of matching the response-time of such a spring-loaded shutter is achieved, and b) Provide a 'DIY solution' / idea for those that wish to - meantime - fix thier PJs, and thereby 'mitigate the risk', at least better than the OEM stepper, does..

    ..Still, some will say '..J, yer making a mountain out of a molehill...', but I say, ya gotta think like this: Let's say you take the PJ - as-is - out to do a gig, and - some bozo, somehow, gets a shot in the face, and even claims he got "hurt".. Calls his laywer / instigates a suit, etc.. Even if it's total bs, you've still got to 'defend' yourself, and IF - and it may be a 'big If', but certainly not-impossible - he has an astute-lawyer, and they hire-out a 'professional evaluation' of the PJ-used, well - low and behold - the thing takes 4x longer to 'stop' an errant beam, in a faulty modulation-control case, than it should.. All-because the ChOEM chose a slightly cheaper component to "save costs", etc.. Where does that leave you? Possibly with the 'bozo' eating yer lunch, dig?

    ..Yeah, it's a 'wild, crazy example', but.. Don't we Live in a wild, crazy world, where truth is often stranger than fiction? Op'ing, not to 'please some Guv', but to truly BE safe / 'CYA' is just 'smart business', these days.. So, mis dos centavos: If you fly w/ the Pluto IIs / Venus, any-other of these Pjs that use the 'stepper' as shutter.. 'CYA', and get a Ledex.

    That is all..
    j
    Last edited by dsli_jon; 02-06-2015 at 02:01. Reason: ...because I am 'mentally ill'.. O_o
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

  2. #2
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    An improvement for sure. But you don't hear the loud "clunk" of the Ledex in the video. I am replacing the Ledex main shutter I originally installed in my projector with a silent GM-20.

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    Thumbs up

    Quote Originally Posted by Photonbeam View Post
    ..you don't hear the loud "clunk" of the Ledex in the video.
    ...That's cuz I nuked the soundtrack off the clip.. ..But honestly, with this lil 'mini-Ledex', it's not nearly as bad a CHUNK as its bigger siblings.. And with the Pj-cover on, I dare say you scarcely-notice..

    Quote Originally Posted by Photonbeam View Post
    ..I am replacing the Ledex ..I originally installed...with a silent GM-20.
    ..Indeed, another fine - and 'US-compliant / CDRH-known' - suggestion, I forgot to mention the GMs.. I chose the mini-Ledex for the low-current draw, size, and ease of making it work with that 'wide paddle'.. Worked out perfect at-height / spot-size, etc.. But, yes, indeed - a GM-20, perhaps in a 'lowboy' (laying flat, vs vertical...) L-mount, and with a wide, stubby flag, would also make a great 'stop-gap' for these Pj's.. Thanks for the additional-411, Chief..

    j
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

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    I like to compare having this shutter to having windows in my house. Yes my house can operate and I can continue to live but for a fraction of the price of the house itself, I can install windows for safety and comfort.
    Freelance Laser Operator in L.A.
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    Nice work Jon. The Ledex's are definitely reliable and fast and I'm sure that mini ledex doesn't make as much noise as the big clunker I was using. Best of all in the unlikely event of failure, it fails in a safe mode. If they're good enough for L'scope's, they're fine for us. Less expensive too. I made a beam table in the '70's using all Ledex rotary solenoids - big ones and you wouldn't believe the noise it made during a chase. Like an old sewing machine or something.
    BTW - Don't forget to add a 1N400x type diode across the Ledex coil to protect the relay contacts. Those solenoids generate enough kickback arc to eat away the relay contacts.

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    ***Cough***

    VRAD506

    ***Cough***
    ***Cough***

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    Quote Originally Posted by dave View Post
    ***Cough***

    VRAD506

    ***Cough***
    ***Cough***

    Yeah, that's basically been my thought too. I thought that was one of the whole reasons it existed and everyone got so excited about them in the first place. It's supposed to be an improvement over the GM-20 (and, readily available).

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    Lightbulb

    Quote Originally Posted by Photonbeam View Post
    ...Don't forget to add a 1N400x type diode...Those solenoids generate enough kickback arc to...
    Sure, good call.. I was thinking that would not be so-critical at only 12V, but.. better safe than replacing yer Relay..

    Quote Originally Posted by dave View Post
    ..VRAD506..
    Yeah, sure, but the Ledex / this mount was proposed so as to be 'DIY-friendly': a) With the L-brakky I found (will-post dims / holes to drill, soon.. it should be a snap for even the lackeyest of DIYers, because no 'additional holes' are needed to be drilled / tapped inside the Pj base-plate (..which is a PITA, at-best..) to-mount - You can use the same holes / screws that hold the OEM stepper / mount in-place.. THAT is worth it, alone..

    ..With either a 'standard GM-20 lowboy', or the 'VRAD' (not-sure what the 'standard' L-brak is like for those, but invariably, it will need more 'homework' / be more werk, than the Ledex-style - why? Beam-height, for one thing..) you'll quite-possibly have to drill / tap other mount-holes in the base-plate, to mount-securely.. Which, again, is a PITA, at-best..There's not much space fer drillin' n' tappin' in that lil' space ..unless you wanna get into taking out all the Lasers and scan-block and OMwho wants to do all that shyte?

    ..Additionally, b) you can simply use the 'OEM shutter blade' that is on the OEM-stepper, so, no need to make a 'fancy-pants one', like the one I used / sho in the pix.. That'll screw right on to the 'armature-plate' on these mini-Ledex.. Done, go have a beer.

    c) I also don't know if, at 12V (the ideal in-Pj option for driving either a VRAD or LEdex - You certainly don't wanna 'unbalance' the 24V off the scanner-PSUs, and you'd also cook the Ledex..) a VRAD's 'swing' (30˚ @ 12V using only one-coil, internally..) would be 'enough' to clear the beam.. Probably, but again, it would take more 'homework'.. Yes, you could 'use both coils' of the VRAD, and get a 60˚ swing @ 12V, but then you're drawing nearly an Amp (~800+ mA) of current, vs the Ledex's ~420mA, tops.. So, it's a 'consideration'..

    ..Point-being, for a 'quickie, low-impact / workload DIY solution', the Ledex was not suggested 'just cuz I had one laying around'.. However..

    Quote Originally Posted by Bradfo69 View Post
    ..It's supposed to be an improvement over the GM-20 (and, readily available)
    ..Indeed, and perhaps the 'best place for this suggestion' (to use the VRAD..) is coming from Bill, himself - to Lightspace, directly.. That-way, they could address whatever 'power-conditioning needs' would be *ideal* for integrating the VRADs (vs their 'stepper'..) in the power-train, and Bill might see yet-another 'hi-volume sales-closure', and YOU-all then might glean the benefit, by having these puppies 'show up', with a much-improved / more-compliant shutter, and w/ no 'DIYing needed'! You can just get yer little HappyMcJector-box from DHL, open, and go get that beer, straight-away..

    ..I shall proposeth-such, to Mr Bill, shortly..
    j
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

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    Fyi, i remember walt saying, he adds his own shutters and swithches for cdrh compliance,
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    Quote Originally Posted by carlos3621 View Post
    ...i remember walt saying, he adds his own shutters and swithches..
    Yep, that's about what I'd expect.. Those 'chinsy' k-switches would be the next-thing I'd nix / swap out for a nice 'EAO' or C&K...And, yeah, the 'scan fail' is, well.. That.

    j
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

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