Problem- Mach3, 203V and steppers losing steps - looking for items to check

[bseibenick]

I am in the finishing stages of full size 3 axis mill conversion using Mach3, a C11 BOB from cnc4pc, Gecko 203v's and Keling KL34H2160-62-8A steppers with a 72V/20A power supply from Keling as well.

For the most part everything is working great except that I appear to be losing steps slowly during a program run. I have a 1800 line program that takes about 7.5 minutes to run and during the program I will lose .028 in the y axis. If i run this program over and over it will lose between .027 and .029 every time. If I jog the y axis along its full 16" length I can hear the smotor skip a step every once and a while. I have mostly noticed this issue with the y axis but believe the x axis is doing the same.

I have tried dropping the velocity and acceleration rates of the motor down significantly to see if that is causing an issue with little change. I have also tried adjusting the step and dir delay numbers from 2us to 15us with no change.

I have the steppers wired in series mode because they use 4.4A/phase in series and 8.8A/phase in parallel. I have the Gecko's set for 5A/phase, so slightly over the rating on the motor. With the system powered the Gecko's are seeing 70VDC and with the motors running full speed it drops to 69VDC.

I have already upgraded my computer to a Pentium D, 3GHz CPU with 2GB RAM. The CPU it running at 10% when Mach3 is running. I am using the onboard parallel port. I have to check in the BIOS to see what mode it is set for as I didn't think of checking that till I saw a suggestion on another thread.

The ideas I have come up with are below:
-Put an expansion parallel port in the computer and try running the machine off of that.
-Enable the Sherline mode to increase the signal duration/delay.
-Change the resistor on the Gecko 203v to see if the 0.6A/phase over the motor's recommendation could be causing an issue.

Any suggestion on further items to check would be appreciated.

Thanks,
Brian

[eaglezsoar]

I would try wiring the motors in parallel and setting the G203v to its max of
7 amps. I hope you have these on a heat sink.
If you have resolved the problem, I would like to know what the solution was.

Regards,
Carl

[ger21]

I was going to second Carl's option. You shouldn't be running the motor over it's rated current, that could be an issue.

[MRM RCModels]

I have the exact same set-up on my X3. Have you tried:

1. Disabling the internet and firewall on the pc?
2. Wiring the X & Y steppers in parallel and only the Z in series?

[allanandr3w]

newbie here same issue on lose but what i experience was that it occur on the same area of the work area.

[allanandr3w]

i downloaded the .pdf file on how to enhance PC for CNC it help a lot but lose step has become my main problem.

[davirg]

Brian,
Did you resolve the problem of losing steps? I have a bridgeport series 2 boss 6 and am having similar issues. I seem to lose .0005 every time I run the program for my part. It seems to happen on all axis. I am using the c11g with 203v geckos.

[atypicalguy]

Add me to the list of people with this problem. I have a CNC router and it routinely loses steps while running a part, to the northwest. My axes seem to run freely and I am only working in MDF so I don't think it's a load thing; I think it is the steps coming out of the machine. I also upgraded to a fast Pentium, and it helped, but I'm convinced Windows 7 is doing something in the background to interrupt the pulse train, or it just can't pump out enough pulses at the current frequency to satisfy the 3-axis simultaneous moves I am asking it to do. I don't want to slow it down too much as I am only going 60 ipm at the moment and it just overheats the end mills if you go too slow.

I am looking for some sort of a controller board solution that will take the parallel port input from the Pentium and output to the same sort of cable going into the breakout board/amp box. I would be willing to pay some hundreds of dollars for an easy to configure solution. SmoothStepper does not appear to be that solution judging from the number of people trying to solve problems with it in forums. Does anyone else have product suggestions?

[davy182]

Here is something to look up. I could have swore I saw some issues regarding quad core processors causing an issue with mach 3 when it switched to the other core because the affinity wasn't set to a specific core. It may not be the issue in this case but worth a look.

[LacL]

I have the exact same setup and same issue. When I use MDI to make moves, I don't seem to loose any steps. Always returns to 0 on the dial indicator. When I run a long program, the parts come out smaller by about 0.045".

I am now suspecting Windows 7 too and found this post after a quick search.

Who else here is using Win 7? I have tried everything to resolve this issue and nothing has worked. Thinking of installing XP if it will solve this.

[Bell 430]

Hello
I had a similar problem when I was setting up my Shopmaster, I founf two problems which I fixed and my machine now runs with no problem.
First put the plug for the CNC package on a surge protector. Second I ran a ground wire form all the steppers to a common ground on the case,then grounded this directly to a ground of the building. I did this about two years ago, I've had no problems since.

[HelicopterJohn]

Hi Leo,

I am running Windows 7 with a Smooth Stepper. Also running Windows 7 in the XP SP3 Compatability Mode. So Far, all is well.

John