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setup
« on: February 24, 2013, 09:30:50 PM »
hello,I need a little help....ok...a LOT of help. Doing the math for my steps per unit, I come up with 20000. But when I calibrate the axis, it changes it to like 150000. but if i set the motors to this 150,000 then the motors stall. why?
Re: setup
« Reply #1 on: February 24, 2013, 09:35:20 PM »
I have my micro-stepping set at 10,200 steps per revolution on the motors, 1 to 1 for gear ratio, 10 revolution per unit.
Re: setup
« Reply #2 on: February 24, 2013, 10:13:45 PM »
given your numbers, 10,200 microsteps at direct drive,* 10 per unit =102,000

Give that a try

John
Ps, do you really need that high a microstep? I understand, correct me someone if I got it wrong but anything over 10 is ineffectual
Re: setup
« Reply #3 on: February 24, 2013, 11:09:25 PM »
microstep is 10. steppers are 200 steps per rev. 1 to 1 gear ratio. and 10 tpi

Offline alenz

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Re: setup
« Reply #4 on: February 24, 2013, 11:41:41 PM »
Re: setup
« Reply #5 on: February 25, 2013, 12:12:13 AM »
If I had read your figures correctly - 200 steps x 10 micro = 2000 steps per rpm.

2000 x 10 tpi = 20,000 steps per inch

At 150,000 - your motors would be trying to spin so slow that they mayappear to be stalled.

Under motor tuning and setup, I would try for each axis as an example -
steps per (20,000)
Inches per minute (12)
Acceleration inches per sec/sec (1)

That should give you the correct steps per - then adjust speed and acceleration to suit the materials you are working with. I work in metric so this is just a best guess from me.

Regards, Danny.
Re: setup
« Reply #6 on: February 25, 2013, 02:13:01 AM »
i can get good movement out of the motors,nice and smooth, when i put in 20000. but when i calibrate the axis in settings,it sets the steps per so much higher. if i calibrate again it stalls the motors and wont repeat the calibration. is there another way to calibrate the axis so the DRO's read correct? I have been watching videos and reading tutorials so much, i may be over thinking.

Offline Hood

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Re: setup
« Reply #7 on: February 25, 2013, 02:55:50 AM »
I much prefer calculating the steps per unit, doing so ensures they will be as accurate as your hardware. Using the calibration is only as accurate as your measuring which is unlikely  to be as accurate as the hardware.
Hood
Re: setup
« Reply #8 on: February 25, 2013, 03:30:17 AM »
i measure the movement with a dial indicator. if i calibrate the motor in the settings menu, it changes the steps to 150,000 steps per unit. the DRO seems to read correct. But doesnt seem right.
Re: setup
« Reply #9 on: February 25, 2013, 03:45:26 AM »
The DRO on the Mach program is only correct because it's calibrated by the figures you input it the motor tuning menu. As long as your figures of 10 microsteps x 200 steps per rpm are correct - then a motor will require 2000 steps per rpm - so 2000 steps per revolution x 10 TPI (or 10 revolutions for one inch of travel) = 20,000 steps for your motor to move your axis one inch.

When you input say, 20,000 then use the calibration function in settings and ask it to move an axis one inch - how far does the axis actually move?

Can work a lot out from that. Danny.