On Friday 22 August 2014 09:29:21 John Alexander Stewart did opine And Gene did reply: > Ben, Riccardo; > > Maybe I have to re-think this issue on my G540. Been off doing other > things recently, so no more work done on my mill. > > Q: no documents close by, so maybe a dumb question. How did you invert > the step outputs?
If you have mentioned your interface method, I have forgotten it, so its possible there is a better way than below. One of the easiest ways, if your G540 brings out both ends of the opto's led, is to swap the two opto's leads around at the + and - terminals. I can do that with my 2M542's also, but no idea unless its in the data on the g540 on the Gecko web pages. I do not know enough about the G540 to know if they do make both ends of the opto's leds available. I just downloaded the manual, and cannot find anything to indicate that it is possible to self invert the signals. This also depends on the output power of your BOB, BreakOut Board. The board I have used twice now is the cnc4pc C1G, which can sink or source 24 milli-amps, more than enough to drive an opto. It can also do a polarity swap on a more global basis by selecting whether the "com" pins are at ground or at the 5 volt rail, which would select the active polarity, but does it for several of the com pins together, inverting things more wholesale if you need a lot of its control inverted. But again, this demands that the opto's being driven have both the + and - terminals exposed for your use. Some of the Mesa cards such as the 5i25 can be programmed in your .hal file so that the output is inverted, and I have done that on two of its stepgen modules because the dir output was backwards. I also could have done this by interchanging the wires to the dir opto in my 2M542's, but that would have required wiring up individual - terminals, which I did not do when I assembled that box originally. I don't know if anyone is making a "by the line" invertor but I could see a market for a few of them. A card with 4 each 4 wide xor CMOS IC's would allow any line of 24 to be inverted individually, doubly useful for you if rigged to db25's on both sides. UNK if anyone is making it though... > Q2: What timing parameters are you using? (steplen, stepspace, dirhold, > dirsetup) The gecko g540 pdf says 2000ns for steplen and stepspace, and 200ns for dirsetup & dirhold. Those latter 2 sound a bit short to me, but thats just an old CET's opinion. There is a page in the wiki that gives recommended times for quite a lengthy list of drivers, see wiki.linuxcnc.org if you have not already. > > Thank you - JohnS > ----------------------------------------------------------------------- > ------- Slashdot TV. > Video for Nerds. Stuff that matters. > http://tv.slashdot.org/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
