On Friday, January 27, 2012 12:08:34 PM Viesturs Lācis did opine: > 2012/1/27 Peter Blodow <p.blo...@dreki.de>: > > Viesturs, > > it seems to me that your laser diode is just acting as a "normal" LED, > > not as a laser. This state is only achieved at a very distinct point > > up on top of the voltage/current curve. The laser diode supply > > electronics must take care of this which is a rather delicate > > controlling task. In other words, the producer of that electronics > > thing is responsible for keeping the correct working point. Mostly > > there isn't much to adjust on them. Are you sure you are using the > > correct supply voltage as specified? If this certain voltage is not > > reached, the diode will not be brought up to the laser point, if it > > is too high, the diode could soon release its magic smoke. > > Thanks, Peter! > Well, it has a separate board with several capacitors, resistors and > something with 3 legs, large heatsink and LM317T written on it. > It is written that it requires 12VDC and consumes ~1A. I am providing > the power from PC's PSU. > Is there perchance an adjustment potentiometer? The LM317T is a linear regulator device and could be made adjustable so as to compensate for the wiring and switching loss in your controller.
> Gene, thank You for explanation! I really appreciate Your help and > detailed information, but all I understood from that - I can extract a > hexfet from dead PC PSU. All the remaining stuff, including use of > hexfet and driving it - it is beyond my knowledge of electronics. > I'm sorry. I try to describe things in understandable terms and obviously I didn't bridge the gap very well. > Laser _was_ burning wood, when attached directly (with less than 1 m > long, 0,5mm^2 wire) to the driver board. It did not want to burn wood > (but at least it was shining), when attached, where it belongs, on top > of the Z plate. There is ~5m of very thin wire, going up there. > Now I cannot get it to shine even when attached back directly to > driver board. That crap is driving me nuts... That very thin wire will probably need replaced with something heavier while maintaining flexibility for long life. Or perhaps the LM317T needs turned up a few hundred millivolts. See the sample schematic shown here: <http://www.national.com/mpf/LM/LM317.html#Overview> Perhaps the maker used a fixed resistor in place of R2, the adjustable one? Given parts tolerances it could already be borderline low. Given that 20-100 millisecond response time probably won't be a show stopper, another thought that may be easier for you to fab on site would be to use your controller circuit to switch a relay. That, and heavier wire might be the better method as opposed to turning the supply up .250 additional volts because someone may replace a future broken cable with an even heavier one which would let the magic smoke out of the laser. > But I also have untuned servo problem running in parallel to this, so > it seems that I am stuck here for at least one more day. > > Viesturs > > ------------------------------------------------------------------------ > ------ Try before you buy = See our experts in action! > The most comprehensive online learning library for Microsoft developers > is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, > Metro Style Apps, more. Free future releases when you subscribe now! > http://p.sf.net/sfu/learndevnow-dev2 > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Suburbia is where the developer bulldozes out the trees, then names the streets after them. -- Bill Vaughn ------------------------------------------------------------------------------ Try before you buy = See our experts in action! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-dev2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
