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Author Topic: Missing Steps - Mach3 - Taig Mill  (Read 9334 times)

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Missing Steps - Mach3 - Taig Mill
« on: September 10, 2006, 09:54:29 PM »
Hello everyone, I have been reading this message board for awhile and using the info to troubleshoot and tweak my setup. I am up and running with all 4 axis; the problem is, I am still missing steps now and then and I can't figure out why. I am wondering if my processor speed is to blame?

My port is testing at 4.98 volts on all the pins I am using. (or zero volts when inactive).

I have my accel and velocity set at what I believe to be a very modest rate.. I have also set my step and dir pulse to 5 (see attached screen shot).

Something strange I should mention.. The step and dir pulse settings seem to reduce by 1 each time I open and then close the motor tuning dialog.

Should I try using Mach2 instead of Mach3?

any suggestions would be much appreciated!

Offline chad

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Re: Missing Steps - Mach3 - Taig Mill
« Reply #1 on: September 11, 2006, 01:10:25 AM »
You might be better off with mach 2 considering your cpu speed. You are running with about half the recommended system for mach3 (1.2 gig or so).

How much ram do you have? is mach 3 the only installed app on that machine? what kind of steppers (or servos do you have) drives? are you loosing steps by measuring the part or can you hear/feel it in the machine? does it do it when jogging or just with g-code?

Re: Missing Steps - Mach3 - Taig Mill
« Reply #2 on: September 11, 2006, 08:18:40 PM »
Hi Chad,
My system specs are as follows..

Intel P3, 498MHz, 256 MB RAM
XP Pro SP2

I installed WinXP in Standard PC Mode as suggested in the optimization file, but I have not yet completed optimizing the operating system. (Just a few of the obvious things).

Mach3 is the only installed app on this system.

I am using steppers, not servos.. (no encoders)..
There are no markings or labels so I can't tell much about the steppers. They are 4 wires and are driven by a StepMasterNC 4-Axis LE controller. I will include a picture of the stepper motor. The Z axis motor is about twice the size of the one in the picture. X,Y and A are as pictured.

I have not lost steps when jogging the machine, only when running code. I can hear it losing steps when I dry run so I know its not a load or torque issue (at least not created by engaging material). I overide the feed rate down to 8 IPM (from 10) and it seems to happen less frequently but it still happens.

I am running a simultanious 3 axis toolpath.

Do you think my problem is processor speed? If your pretty sure thats what it is, I have another machine I could switch to. I am using the other machine for CAD/CAM and would rather not dedicate it to Mach if I can avoid it.

Thanks for helping  :)

Offline chad

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Re: Missing Steps - Mach3 - Taig Mill
« Reply #3 on: September 12, 2006, 04:12:23 AM »
The computer is just a little too wimpy for mach. The amount of ram is a problem too.  Both of these are combining to give you your poor performance.
OK jog and poor gcode are a sure sign of the processor being too slow. 
The ram is affecting things too. Win XP pro all by itself can gobble up to 200mb of your ram. If you have on board video that will take ram from the system too ( and usually causes other problems with mach 3) , same for on board sound (although not as much).
What happens when you get low on Physical ram is the processor has to take a break from running things (like mach) and store some virtual memory on the hard drive. Reading and writing VM like this is time consuming and requires a lot of processor cycles, On a already slow processor and HD / Io subsystem.
Mach takes takes lots of "liberties" with the 2k/xp kernel as it is to get consistent timing out of the parallel port. Combine this with a slow system and you will get exactly what you are describing.

Sorry but it just isn't possible for mach 3 to run well on a machine like that , it is just what it is. 

Good luck,

PS. You can have a brand new2.66 GHz nice machine now days for about $300. That would make a nice new cad/cam computer ;) make sure it has at least 512mb of ram. For cad/cam a gig would help lots.

« Last Edit: September 12, 2006, 04:14:09 AM by chad »