Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Glenn on April 24, 2007, 07:31:42 AM
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Hi guys,
In motor tuning, is it unusual to run 40,000' steps per' to get the
inches to be exact on a linear movement? And can this high number keep
me from getting really fast IPM's? My motors won't run very far before they squeal
and lose their place.
Is this a situation where some of you choose to use sprockets to turn the motor half as
fast as the screw you're turning?
Thanks,
Glenn
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Hey Glenn,
That sounds a little high to me but, there really is no such thing. Steps per dictates the degree of resoloutin you have. The min. amount of steps you can send is 1. At 40,000 you have a resoloution of .000025. Steps per can limit your max speeds. This is why, you can only generate 45,000 pulses per second. So, 45,000 X 60 = 2,700,000 pre minute. For your setup of 40,000 steps per the max speed would be 2,700,000/40,000 = 67.5 IPM at 45Khz. There are things that can be done to get higher speeds though. Gearing, drives, leadsrew pitch, etc. As for yours stalling, try slowing things down in you motor tuning and see if you can get it to run smooth and not skip steps. Lots of things can cause that. Motors that are too small, power supplies that are too weak, a mechanical bind, too much tool load, etc.
I hope this helps
Brett
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Hi, Glenn
See your using Gecko's, sounds like your using 10 micro step mode ?.
Dose it have the G901 Step pulse multiplier board, For use with G201 and G202 drives 1, 2, 5 or 10 step pulses out for every input step,
Jumper settable resolution.
Pull the cover off of one of your Gecko's and check is there a plug-in board on top of the main board (Just about half the size of the main
board), If so you can use a lower micro step setting 1, 2, 5, Check the Gecko website for G210 and compare the board layout.
If not, what's the ratio between your stepper and lead screw and the lead screw turns per inch.
Check this Out, Chip
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Thanks Brett- and Chip!
It sounds like you're on the right track on this one too!
Brett, before, when I would slow them down to see if it would
run, I would go as slow as 10-12 IPM's. Not slow enough, they faulted, so I went all the way down to 3 IPM's
as per your great advice, and viola, that bad boy runs now without any faults at all. YES!
I increased 1 IPM until it got to 7 IPM'S without faulting.Neat, but too slow for real
productivity. We're on the right track.
Chip,
Yes, this sounds like what I need. Are you saying that in some set-ups, it would be possible
to only send 4,000 pulses to the g201, instead of 40,000 (which is my current system)? And still
travel an inch for an inch?
That would be the solution I seek.
I've looked over the g901's literature, and if I have read it right,(please correct me if I'm wrong), it would allow my computer to send
1/10th the pulses to the g201's and still be inch for inch correct?
OR, do you think that the g201 can be adjusted to stop making 10 micro steps? Unclear on that one.
The leadscrew turns per inch are 20 to 1, .05" pitch x200 steps per rev= 4,000.
Thanks,
Glenn
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Hello to all,
I have a similar problem after the last upgrade to Mach 2.65, My Z axis for it to go down 1" the steps whent from 2000 to 20,000 but this creates a problem when I try to cut circles I get and oval. I have try to set the step per unit but the Zaxis won't come no where close to the actual travel of the screw. I even try a full reload of Mach and it did the same exact problem :-\
Any ideas?
Thank You,Marco.
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The steps per inch is not a number you can just pick, or tune. It must be selected to match the mechanical elements of your machine. You must know the pitch of your leadscrew, the pulley ratio, the number of steps per rev of the motor.
Mach does offer a calculator to help, you guess at a number, command a 1" move and measure how far it actually went. Mach can then calculate what the number should be.
Reloading Mach wont help, you simply have to get the number set correctly. It sounds like you might have lost your xml file when you upgraded Mach. That does happen sometimes. Use the motor tuning screen to set steps per inch correctly and you should be good to go.
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Hello Ron,
Well I'm new to this and I 'm not use to the set up on the machine just to change on their own,like I said before the steps was set at 2,000 and later the number is at 20,000 that is very weird :-\
I will try Your sugestion.
Thank You for the help,Marco.