Need Help!- Mach3 wont work, going back to EMC

[JeLC]

I've had my machine up for about a month now. I originally started out with Linux/EMC but I had latency problems. Not being proficient at Linux, I decided to try XP with the trial version of Mach3 and my machine worked OK, but I'm losing steps extremely bad on the X and Z axis. Y is not as bad, but is still losing a little. I'm running a 2.4Ghz DFI LanParty MoBO with 512Mb ram and a Matrox G450 32Mb video card. The computer is dedicated to my cnc machine, so there is no network card and no other programs running except the machine controller software. I'm using the Gecko G540 driver and Keling 378oz motors. My table is approximately 34" (x) by 25" (y) by 5" (z).

I've seen posts in this section of people who went from XP/Mach to EMC with good results. I've read the sections about disabling the SMI, and right now, don't have a clue how to do it, but I guess I'm about to spend some time learning Linux, like it or not.

Now for my questions

1. Will more memory help the latency problems? I have two open memory slots on the MoBo, so I could easily upgrade. If so, how much is recommended.

2. I installed the Matrox graphics card into the Linux system before I formatted and loaded XP, and Linux did not recognize the card. I was stuck at 600X800 resolution. Is there an open source (Linux compatible) driver for the G450 card.

3. I've read that disabling SMI can cause the MoBo to overheat. Can I use a large external fan to keep it cool and expect acceptable results.

4. What value of latency is acceptable. When I ran the latency test while still running Linux, I was getting upwards of 46uSec at idle, and when taxing the system by playing some games, moving files, etc, it would occasionally spike to 50 and 60 uSec. (and those values may be nano seconds. You people more familiar with this than me please correct me if I'm wrong).

5. What other tip/tricks are out there for me to try to minimize the latency problem. I don't want to scrap this thing, but I have just about reached my spending limit, at least until I get some better cuts than I've gotten so far.

6. Should I get the latest version of Linux/EMC or would I be better off with one of the older versions. I'm right now downloading Ubuntu 8.04 with 2.3 (I think) EMC. It looks to be just recently released. I already have an older version of Ubuntu (live cd) and if I recall correctly, it's version 6.xxx with EMC 2.2.6 (again, I hope I'm remembering correctly).

Any help and or recommendations will be appreciated.

[dertsap]

Originally Posted by JeLC I've seen posts in this section of people who went from XP/Mach to EMC with good results..

Ive had reversed results , my system runs much better and faster than i was ever able to get with emc . linux was much harder on resources .
is there any chance the accel was set too high , generally lost steps are due to accel or velocity being set too high

[JeLC]

On recommendation from someone at ArtSoft (Mach3), I have lowered the Acc/Vel down to a crawl on all axis. (cutting at 10 IPM) And I've also, (again from ArtSoft recommendations) added 1, 2, 3, 4 and 5uSec to the step and dir pulse widths. (It appears in the bottom right corner of the motor tuning dialog under Config in Mach3 and I've tried all of the above values).

Just for an example, I tried another test cut today. Did a V-Bit engrave on 3" letters .3" deep on MDF. I have to split my toolpaths and cut the letters separately. (500 line max on trial Mach3) I checked the z height after each cut. Just cutting a simple 3" high letter, and my Z would be about .3" high when I go back to (work) zero. And the bevel would be off in the x direction about .1".

I have threads about this in the Mach and DIY sections on here and the Mach3 group on Yahoo, so I've tried a lot of things to get this fixed.

Looks like my only alternatives is to get EMC running and work on the latency, or go with another MoBo. And I hesitate to buy another processor/MoBo in fear of ending up with the same problem. The system I'm using works great for a general purpose PC, but it just doesn't like to run real time.

[dertsap]

i honestly have a hard time believing mach could be causing the lost steps , I run 2.5d profiles that will run for hours without any trouble , youve got plenty of computer to run mach smoothly , is it possible that its a mechanical issue and not a software issue
what type of machine are you running with it ?

[JeLC]

I'm running a Gecko G540 with 387oz Keling motors. I have 48" (x), 36" (y) and a 12" (z) Acme lead screws (all 1/2"-10 pitch). I'm using the Fine Line Automation anti backlash nuts. I constantly check the tightness of the set screws on my couplers between the lead screws and motor shaft, so I'm confident they are not slipping. I also have gone thru the steps per unit calibration many times, and it is dead on. In other words, I tell it to travel 8 inches, and it measures 8 inches)

I built a variation of the JPGO (I think that's the name) machine from the DIY section. I'm using 1 1/2" black gas pipe with roller skate linear bearings on the x and y axis and 1" pipe on the Z. It's built out of MDF, but it's is built well and it's square and plumb in all directions. I've been a wookworker all my life, so building the wooden parts were easy. I have good woodworking equipment (table saw, router table, chop saw, radial arm, etc) so I know the table is built right.

I've watched and rewatched the Mach3 support videos until I almost know them word for word. I really don't know what else to try with Mach3.

[nikodell]

I had poor latency with a G400 Matrox card on the system I am setting up so i switched it for a Nvidia card and the issue was gone.

[JeLC]

I bought the Millennium G450 because of a few people on here saying it would work help. I originally had a 32 Mb Nvidia, and also tried an ATI 64Mb card, and neither of them helped. All had just about the same latency under Linux. I haven't tried the two other cards on the XP system, so I guess that's something I could try. I'll do that tomorrow and see what happens.

[nikodell]

odd I would suspect that you may have some other issue than

[JeLC]

Before giving up on Mach, I'm going to change out some things. I'm going to try a PCI Parallel port and a new cable. I'm also going to change out the wiring from the Gecko to the motors. Try to find a higher quality shielded cable at a lower gauge. I'm right now using 22 gauge shielded, and will replace it with 18 gauge shielded.

Just start eliminating anything that could be causing problems and worry about the latency last, because that basically calls for another system. Hopefully the parallel port will help a little, and another cable can't hurt, I hope. The 18 gauge wire was really what I should have put on originally, but I had the 22 gauge laying around and decided to try it.

[solodex2151]

You should check your nuts and see that they are properly aligned. The clue that things are misaligned there is that it gets harder to turn as the gantry approaches the end of the travel. This is because things are binding.

To get this aligned, first ensure the ACME nut is riding on the screw and that the nut sits precisely on the top of the gantry's bottom rail. I left the bearing blocks loose and rolled the gantry to the far (non-motor) end of the table. At this point, the far-end bearing block will drift into place and you can tighten that down. Then roll the gantry to the other end. With those bearings and motor mount also loose, they will want to drift into place. Let them go where they want, and then tighten everything down. The crank the gantry to the middle of the table, and using piece of plywood across the short axis of the table, ensure the height from the bottom of the ply to the drill rod is consistent. Manually cranking the drill rod using the coupler for extra leverage should reveal that the motion is smooth across the entire range of usable motion. If it's not, try again.

Note, too, that if your 8020 ends aren't perpendicular to the sides, then the end bearing can easily distort and bow the leadscrew. You'll see this if the gantry is midway and you have a gap.

Check this and your other mechanicals before you continue. You should be able to turn all of the leadscrews by hand.

Regards,

Nate
Fine Line Automation

[tumutbound]

2. I installed the Matrox graphics card into the Linux system before I formatted and loaded XP, and Linux did not recognize the card. I was stuck at 600X800 resolution. Is there an open source (Linux compatible) driver for the G450 card.

I'm running a Matrox G450 at 1900x1200 resolution without any problems. This is with a standard Linux distribution, no additional drivers.

[LeeWay]

Just for giggles, try the Sherline mode. For some reason, this has cleared up issues like yours for other with the 540.
Not sure why that fixes it, but it does in some cases.