Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Bill CNC on December 13, 2007, 11:03:38 PM

Title: Micro-stepping Question
Post by: Bill CNC on December 13, 2007, 11:03:38 PM

Hello All,

I was wondering about micro-stepping, I have my motors tuned to full steps and I want to do 1/2 micro-stepping.

Do I just double what I was using on full-stepping?

Thanks
Bill

Title: Re: Micro-stepping Question
Post by: Overloaded on December 14, 2007, 12:16:30 AM

Yup,
If your motor is 1.8 deg. 200 ppr full step, 1/2 step will be 400 ppr.
                                                           1/4       "          800  "
                                                           1/8                  1600
Of course you have to set the step resolution on the driver.
I've seen   1/256 step,   51200 ppr.   Now that's microstepping.

Title: Re: Micro-stepping Question
Post by: Bill CNC on December 14, 2007, 01:43:09 AM

Hello Overload,

That's what I thought. I am running with a Hobby CNC pro board so I just removed the #2 jumpers of their axis.

Thanks
Bill

Title: Re: Micro-stepping Question
Post by: jimpinder on December 14, 2007, 05:18:32 AM

Hello Bill - seeing you are watching the topic.
The drivers cards for the motors control how many pulses they put out to the motors, to move one step of the rotation. On my cards you can switch between 1,2,4 and 8. That moves your motor 1 step. If you have 1.8 degree motors, then you need 200 of these to turn the spindle 1 revolution.

Mach3 then needs to know how many pulses you need to move 1 inch (or 1mm). So you start at your step rate multiplied by your motor angle multiplied by any gearing multiplied by your leadscrew.  e.g. mine is 1/8 step, 1.8 degree motors, 3 to 1 gearing and a  1/10inch leadscrew, so Mach3 needs to put out 8 x 200 x 3 x 10 i.e. 48,000 pulses per inch.

If I have to put out 4.8 pulses per 1/1000th of an inch it is certainly accurate.

Jim Pinder