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Author Topic: Need help with steppers- changed driver microstep now travel is way off  (Read 2886 times)

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Hello,
I have run into another problem. When I setup Mach3 initially I used the microstep settings on the stepper drivers; they were set for 8 microsteps, or 1600 steps/rev. After researching, I found that for my system the 4 microstep setting (800 step/rev) would have a resolution of .001", so I thought I would change the microstep settings on the driver boards to the 4 microstep setting. My reasoning was that the extra steps were wasted and decreased system efficiency.

After I made the changes I restarted the machine & Mach3. Then I made the "steps per" changes in Motor Tuning after the restart.

I then tested the axis travel movement. The motors were extremely slow. The X,Y,Z DRO's show 1" of travel for only a fraction of an inch actual travel. Axis should be travelling my table (24" x 36") but only travel a few inches for what Mach3 thinks is full travel.

Something got messed up, maybe I did not follow proper procedure or missed a setting- and maybe what I did was not necessary?



Forgot to add,

X, Y Ballscrew 10mm pitch, 2.54 TPI

at 1/4 microstep should be 2032 steps per inch.
at 1/8 microstep should be 4096 steps per inch.

Z Ballscrew 5mm pitch, 5.08 TPI

at 1/4 microstep should be 4064 steps per inch.
at 1/8 microstep should be 8128 steps per inch.

Wrong or right?

Offline Fastest1

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First of all your steps werent wasted. I would use the higher amount of steps my self. But for the sake of calculations

If you chose 1/4 micro stepping with a 200 step/1.8 degree

200 x 4 x 2.54=2032
200 x 8 x 2.54=4064 (not 4096) though I think you just transposed the numbers of your 5 & 10mm screws

Your formula or thinking is correct. Did you restart Mach after the changes?

Will your controller let you set a 10x microstep?
200 x 10 x 2.54=5080 or a theoretical step move of 1"/5080=.00019685
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
I did reset Mach3.
The controller is Leadshine M860, it will do from 2 to 200 microsteps.

My thoughts on the microstep was that since the 1/4 setting works out to .0001" revolution, and it is unlikely my table will resolve to even that.

Thanks!

Offline Fastest1

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You have the formula down. Go ahead and try the different settings. It is just a few calculations. Run a code a see if there is a difference in finish and or loss of steps. Cant hurt.
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
The stepper scalling is fixed now. A newbie mistake... The stepper drivers have a dipswitch for setting the microstep and current limiting. I had the settings correct, only I mistook the switch's on for off. After I realized the mistake and set the switch correctly everything returned to normal. I have been having trouble sleeping lately so I would work on the CNC project instead of lying in bed trying to go to sleep. Probably not in my best form in the middle of the night.

Thanks for the help.

Offline Fastest1

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Who can sleep knowing our machines are having problems? We all stay up too late and make decisions when we are tired, or try to understand something.

Btw, Those damn dip switches are always hard to tell which way is on. Some manufacturers even have it backwards in their literature. Now that will be something you will check for in the future too. Soon there will be no mystery to Mach 3, then 4 will come out ;-)
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)