Hi Maybe use shielded cable can help. I use Aigus cable CF31. > I've read several of the other replies. They all seem to have good > advice, but what I would tend to look at first is the grounding of your > signals. It could be that your direction signal could be misinterpreted > by the driver board because your reference point (ground) isn't as quiet > as it needs to be to get a 100% consistent signal. > > Sometimes the solution is just a larger ground wire, sometimes some > signals need to be isolated from ground to receive the signal > consistently. Do you have access to an oscilloscope? If so, ground the > scope to your computer and read the ground line on your driver board. If > the voltage at the driver should be only tenths of a volt. If it is > greater than that, some changing is in order. > > I also divide and conquer when I can - halscope is a good window into the > EMC actions, and the scope is the tool for outside the computer. > >> From: jpe...@peasej.com >> To: emc-users@lists.sourceforge.net >> Date: Sun, 5 Jul 2009 12:25:16 -0700 >> Subject: [Emc-users] Weird EMC2 tuning issue (direction >> reverses intermittently) >> >> I am working on tuning my homebuilt HobbyCNC machine with EMC 2.3. I >> am using the HobbyCNC EZ driver board to interface with my PC. I have >> things working, but am working on tweaking the ini settings to get as >> high of feedrate as I can reliably. >> >> One mysterious issue I've seen that I'm trying to figure out is that >> very, very rarely, a movement command to the milling machine will make >> an axis move the correct distance in the INCORRECT direction. This can >> happen either when running a gcode program or manually jogging the >> axis in a direction. If it occurs during a jog, usually all I have to >> do to fix it is stop jogging and then start again. >> >> The computer interfaces with the driver board using the normal STEP, >> DIRECTION signals for each axis over the parallel port. >> >> The question is, where do you think this issue is being introduced? It >> seems unlikely that EMC2 could be getting the direction wrong in >> isolated cases, but, to me, it seems equally unlikely that the driver >> board is driving a particular direction incorrectly in isolated cases. >> This might also be a symptom of operating at too high of a feedrate >> (in the current case I have been trying to make 40 inches per second >> work), but I'm hoping to hear from someone who has seen and fixed this >> issue before I try dropping the feedrate. Like I say, this issue crops >> maybe .05% of the time - very rare, but enough to affect the overall >> reliability of my machine. >> >> Any ideas? >> >> >> ------------------------------------------------------------------------------ >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users > > _________________________________________________________________ > Lauren found her dream laptop. Find the PC thatÂ’s right for you. > http://www.microsoft.com/windows/choosepc/?ocid=ftp_val_wl_290 > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users >
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