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Thread: interlock connections

  1. #1
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    Default interlock connections

    What's up everyone? Continuing my first laser projector build. Got the case assembled and painted. Finished the AC to PSU connections and soldered cables to the ilda connectors.
    A bit confused about how to connect the interlocks.
    The diagrams on the internet ilda diagrams just list pins for interlock A and B, but don't they have a + and -?

    My drivers have an interlock + and - pins so I'm not sure how that is connected to the pins on the ilda connector. Help.

  2. #2
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    This is a closed loop thru the DAC from A to B, so no polarity.
    The idea is to connect a relay on your DC laser drivers. Relay is normally OFF (when not energised), and when ON, it supplies DC power to your laser drivers.
    Control relay (solenoid) current goes to A and 'returns' from B. A and B are 'shorted' when ILDA/DAC are connected...so relay is ON=DC on laser driver. If you pull out ILDA connector there's no continuity from A to B=relay goes OFF.
    Sorry crappy hand draft..hope it helps.
    Click image for larger version. 

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    Last edited by jors; 02-06-2017 at 07:01.

  3. #3
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    mixedgas is offline Creaky Old Award Winning Bastard Technologist
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    Default

    What the interlock is at the DAC/control end is a short circuit on the connector from pin 4 to pin 17, and generally sized to support a current of no more then one hundred milliamps.
    It is up to your projector to sense if this short circuit is present or not... All it does is tell your projector if a control system is attached...
    ~
    Since your drivers probably are not designed to sense the interlock contacts in parallel, you probably need to do that with a small 5V logic level relay with a high coil resistance. Then supply a relay contact for each driver.
    ~
    If you need a better explanation of the standard signal levels, click on the second link from the left, here...
    http://www.photonlexicon.com/forums/...ILDA-STANDARDS
    ~
    Steve
    Qui habet Christos, habet Vitam!
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    When I still could have...

  4. #4
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    ...which leads to all kinds of problems if projectors of different make are daisy chaisy chained...

  5. #5
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
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    Back in 1990 no one envisioned needing a current based loop... A contact closure was fine... I know, problem today if you do not have skills to make your own ILDA splitter..
    Steve
    Qui habet Christos, habet Vitam!
    I should have rented the space under my name for advertising.
    When I still could have...

  6. #6
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    Lightbulb

    Here's one design that Works well, that is a bit more 'inclusive' (provides for door / case interlocks / keysw / start/restart button, E-Stop, etc)..

    Click image for larger version. 

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ID:	51697 ..used to have this up on the currently-awol 'Wiki', and I am Sure many could suggest a more 'elegant' relay, in-place of the Omron, there (Omron MY4N-DC24 in a PYF14A-N socket (or, equiv..) but.. a) This Does work / has-been used in CDRH-approved PJs, and b) I don't claim to be a 'circuit designer', so.. Don't shoot the messenger..

    ..Though this version was more the 'base' for inclusion of a separately SSR-gated Hard Beam Shutter (GM-20 or other..) The 'Interlock Loop', there, is where you would loop-in a separate SSR on the 'signal-side', to 'gate' the DC to your Laser Drivers, but.. I, personally, would prefer to simply 'gate' any *Modulation Signals* to them (vs DC Power) Why??

    ..Well, for example, if your Laser Drivers also have a built-in TEC-driver / heat/cool management circuit, and someone (or You..) trips one of the interlocks or the E-Stop, you're simply killing the Light-output, and not the Cooling circuits / fans (possibly..) I'd just see that being a smarter way to 'pamper' your diodes / dpss x-tals (avoid 'hard power-downs', especially if they've been running hot, etc..)

    ..Too, this is where (in My 'old-skool views', at least..) a Keyed, Hard Beam Shutter is still a more preferable / essential safety-element (over 'gating' signal, and/or DC-to-Drivers, etc, alone..) since a Hard Shutter will even prevent 'transients', AS a driver is being powered up / down (..Especially in-cases where AC-power is lost to the whole Unit..) from 'spitting a beam', even with an SSR, etc, in-place..

    ..I also endorse Sir Rob Stanley's ('stanwax', here on PL..) ILDA I/O boards - http://www.photonlexicon.com/forums/...highlight=ILDA ...but this little 'JonCo' number Will work, if yer more into 'DIY' / the wallet is on a diet, etc..

    Fwiw.. Cheers..
    j
    Last edited by dsli_jon; 02-06-2017 at 16:37.
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

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