G540 STEPS/REVOLUTION

[SCYBUCK]

Got the Openbuilds Kyo Sphinx moving today along all three axis! Thanks to CNC Keith for the resolving the 4th axis challenge. Now working to make sure that 1 inch in the Y direction is really 1 inch.

The leadscrew is a standard Openbuilds Tr**8-2p. One turn advances the nut 8mm. The steppermotors are regular 4 wire, 1.8 deg/step motors.

I can seen no document that tells me exactly how each driver in the G540 figures out the step mode. Any comments? What values should the Steps/Revolution and the Overall Turns Ratio be set to and why?

I have no doubt that I can work through numbers that will result in the machine moving the correct distance. However, it just seems appropriate that I should actually have a solid comprehension of how the ratios are worked out.

THanks for Noticing,

Scybuck

[Gary Campbell]

Steps per revolution should be what the drives are set to. 1/8 or 1/10th for example. For 1/10 steps per revolution would be 2000.

For the turns per inch, the number would be 1 inch / 8mm or 1/0.31496 or 3.175 turns per inch

[SCYBUCK]

Thank you, Gary. I wound up using 1997 for the Steps/Revolution and 8 for the mm/Turn.

[cnckeith]

hello.

1997 is not a valid steps per rev value for the G540.

never adjust steps per rev to change the distance that the machine moves.

motor turns per inch is a mechanical constant and steps per rev is an electronic value

we don't mix the two values like mach and others to adjust commanded distance.!:-))

set the steps per rev to match your drive settings and then leave it alone!

then go and adjust the axis motor turns per inch value to tweak in the 'overall turns ratio' of the machine. there are posts, videos and tech bulletins covering this subject.

[martyscncgarage]

Thank you, Gary. I wound up using 1997 for the Steps/Revolution and 8 for the mm/Turn.

Nope,
Assuming a standard 200 steps per rev stepper motor, G540 microsteps by 10. You should use 2000 steps per rev.
You should have checked the appropriate radio button in the Wizard for G540 it would have set this for you.

I have a video that discuss how to setup your screw. Search YouTube for martyscncgarage

As Keith said. you leave the steps per rev at 2000....use motor revs per inch

Marty