Safety Shutter control

Discussion in 'Laser Safety' started by Flavio Spedalieri, Apr 29, 2004.

  1. Greetings..

    I am looking into advanced safety shutter control for a new projector I am working on..

    I will be employing two physical mechanical shutters, one shutter for normal show control / beam shuttering. The second shutter being an emergency shutter - this is on top of laser blanking..

    I am looking at different monitoring methods, such to be able to trigger the shutter in an emergency situation such as scanner failure. By monitoring the input signal to the scanner drivers and the actuall scanners, should a fault occure where the scanners stop (yet you still have the X-Y data available), the show control / beam shutter will not close (thus you will have a laser entering the scan-block, and a static beam output..

    I realise that currently, beam shuttering can be relied on by AOM/PCAOM and physical mechanical shutter, yet how are the scanners being monitored such to trigger the emergency shuttering / attenuation of the laser such not to enter the scan-block ?

    Thanks
    Flavio
     
  2. Pangolin

    Pangolin Staff Member

    Hi Flavio,

    Yes, this "monitoring the input to the scanners and comparing it to the actual position" is employed by several so-called scan-fail systems on the market today. BUT, if not done properly (and in my opinion, so far it has not been done properly) this is froth with problems...

    In any event, as for the shutter, I strongly recommend shutters from NM Laser Products. Please see their site at: http://www.nmlaser.com/

    NM offers a broad line of laser shutters that are very fast. Actually in one case I have seen their shutters used for blanking!!

    Bill
     
  3. luminavp

    luminavp Active Member

    Bill, out of interest, what IS the proper way of doing feedback analysis in scanfail boards?
     
  4. Pangolin

    Pangolin Staff Member

    Hi Luminavp,

    You ask an interesting question, and in fact, a philisophical one. Let me point out that many so-called "scanner safety" boards verify that the scanner is doing what the control signal tells it to. But what if the control signal itself is the source of a problem? Even if currently-available "safety" circuits did a good job in this regard (which they do not) there are a handful of other failure modes which are completely overlooked by current "safety" boards.

    Bill
     

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