On Friday 28 June 2013 13:08:47 Hugh Currin did opine: > Folks: > > It is time to update my CNC controller. I'm now using a 1GHz Pentium III > computer, with 4Mb memory, running EMC2 2.0.3. It works fine but would > like to access CAD (Varicad) and CAM (Sheetcam) software in the shop. > This old computer isn't up to running those. I have a Lenovo desktop > I've planned (for a couple of years) to move to the shop, however after > loading LinuxCNC the latency (300,000) was terrible. After some fiddling > and tuning I gave up on the Lenovo. > > So, I read the Intel D525MW miniITX board works well with LinuxCNC. Too > old to be found through NewEgg, etc. but I found one through Amazon. It > shipped from Mega Micro Devices but I don't see it on their site. I've > mounted it in a miniITX case with one 2Gb memory stick, 500Gb hard drive > and CD Drive. I put a PCI single parallel card in but don't currently > plan to use this second port. > > I loaded LinuxCNC 2.5.2 without a problem. Latency tests show "Jitter" > around 16.3 uS (16,300 nS) out of the box. After turning off > hyper-threading this came down to around 10 uS, but I didn't run the > test for very long. I used the "Stepper Configuration Wizard" to build > the *.ini and *.hal files. All seemed to work. > > I then connected the D525MW up to my converted mill. It uses a PMDX-131 > breakout board with three (XYZ) Gecko G202 drives. This circa 2007 > controller works very well with the old Pentium computer. > > Well, the motion using the D525MW is very ragged and doesn't conform to > the requested motion. I have Trav-A-Dial readouts on X and Y which show > the ragged motion. It's a ragged motion all the time, not a burp once in > a while. Asking for G1 X0.5 F10 gives a jerky motion of 0.1" or 0.2". > Something is terribly wrong. I don't think this is a tuning problem and > I've tried different BASE_PERIODS without any noticeable change. I > pulled the second parallel port out with no change. > > I don't know what else to do. I compared the *.ini files from EMC2 2.0.3 > and LinuxCNC 2.5.2 and don't see anything amiss. The pinout in the *.hal > files seem the same. Also, there is action on X, Y and Z when jogged > leading one to believe the pinout is OK. > > I spent a few minutes trying to configure it to use the PCI parallel > card rather than the onboard parallel port. I found the card (lspci -v) > but couldn't get it configured in LinuxCNC. The I/O ports are at 1000, > 1010, 1018, 1020, 1028, & 1030 but I may have a format error when I > enter these into the HAL file. > > I hope there's something simple amiss and someone can assist me in > finding it. I can post the configuration files if asked, please let me > know which ones and how best to include (inline, attached, etc). Any > additional tests to run? > > Thank you in advance. > > PS. I seem to go though this every five years or so when I get the bug > to update my controller. Please bear with me.
Happens in the best regulated families. :) WHat I suspect is happening is that the newer LCNC has the ability to reset the output port in a short time, an ability that doubles its theoretical output stepping rate. ISTR reading somewhere that the Gecko 202 has slow inputs. Slow opto isolators's would be my guess. In your .hal file, if the reset time is less than the gecko needs, you'll probably get funkity results as you describe. Don't quote me as my wet ram is 78 yo, and I don't have any Gecko, but ISTR seeing someplace that it needs around 5 microseconds for any input change to be properly recognized. The my-lathe.hal file for my lathe which uses 2M542 motor drivers is on my web site at the lathe-stf link, site in the sig. This will give you the syntax examples as to how to both implement this improved function, and how to set the timing, which for the Gecko's I would start at something known to be slightly longer than they need. I am still fiddling with the timings for the 2M542's, reducing it by .1 microseconds if and when I think of it. That is a long and complex file, and the settings in question are near the bottom of that file. Look for lines containing "parport" and "reset". Also check the loadrt parport line at the top of the file, there might be something there. In any event, IWFM, YMMV. 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> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> Fishbowl, n.: A glass-enclosed isolation cell where newly promoted managers are kept for observation. A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
