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Author Topic: SmoothStepper Motor Steps Per Unit  (Read 451 times)

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SmoothStepper Motor Steps Per Unit
« on: January 12, 2019, 07:35:21 PM »
I'm running a SmoothStepper ESS with a Gecko breakout board. I'm having to set my nema 23 motor steps per unit to 40000 to get correct travel. Is this common? Seems high.
Taig Micro Mill. 1/4-20" lead screw. Powered by 1.25hp router with a 4:1 pulley reduction. Driven by Ethernet SmoothStepper to a Gecko 6540. Nema 23 motors. 3 Axis.
Re: SmoothStepper Motor Steps Per Unit
« Reply #1 on: January 12, 2019, 07:49:46 PM »
Hi,
tell us about your machine...what ballscrews for instance?
What gear/belt reduction between the stepper and the ballscrew?
What are your native units?

Craig
My wife left with my best friend...
     and I miss him!
Re: SmoothStepper Motor Steps Per Unit
« Reply #2 on: January 12, 2019, 08:49:53 PM »
Hi,
tell us about your machine..
Craig

Hi Craig,   It's a Taig mini mill with a acme 1/4-20 TPI lead screw that is directly driven by the nema 23 stepper. Working in inches. Using the Ethernet version of the SmoothStepper board.
Taig Micro Mill. 1/4-20" lead screw. Powered by 1.25hp router with a 4:1 pulley reduction. Driven by Ethernet SmoothStepper to a Gecko 6540. Nema 23 motors. 3 Axis.
Re: SmoothStepper Motor Steps Per Unit
« Reply #3 on: January 12, 2019, 09:41:49 PM »
In that case your 40000 steps per inch would be correct.

20 TPI  x  200 full-steps/rev  x 10 micro-steps/full-step  =  40000

Steve Stallings
PMDX

Steve Stallings
www.PMDX.com
For PMDX product support, please use PMDX forum or direct email for quickest response. We do not use this forum as our primary product support site.
Re: SmoothStepper Motor Steps Per Unit
« Reply #4 on: January 13, 2019, 11:54:50 AM »
In that case your 40000 steps per inch would be correct.

20 TPI  x  200 full-steps/rev  x 10 micro-steps/full-step  =  40000

Thanks! Just curious where you got the 10 micro-steps info from?
Taig Micro Mill. 1/4-20" lead screw. Powered by 1.25hp router with a 4:1 pulley reduction. Driven by Ethernet SmoothStepper to a Gecko 6540. Nema 23 motors. 3 Axis.
Re: SmoothStepper Motor Steps Per Unit
« Reply #5 on: January 13, 2019, 12:13:15 PM »
Hi,
10 microsites per fullstep is built into the G540.

Craig
My wife left with my best friend...
     and I miss him!
Re: SmoothStepper Motor Steps Per Unit
« Reply #6 on: January 14, 2019, 11:31:07 AM »
10 microsites per fullstep is built into the G540.

Thanks!  So I got this all setup and calibrated. I'm having a few issues:

1: When I put jog speed way down low and attempt to bring the end mill close to the part to touch off by continually tapping the arrow key I have mapped to jog, I see the head doing a small bounce back. Am I just not sending enough of a signal or something by having the jog speed so low and then doing a tiny tap on the jog key?

2: When trying to set backlash compensation on the Y axis no matter what value I put it doesn't seem to be compensating. I've checked that it's the correct motor. I did see that I was setting it in Mach vs the SmoothStepper plugin, and that I did not have the backlash compensation enabled in the SmoothStepper plugin, but I was able to get the compensation to work on the other two axis, so im thinking that's not the issue. I haven't had time to check what happens if I try to set it via the SmoothStepper plugin.

3: I'm running a demo of Mach 4. Is this why the return to work zero button doesn't work? I am guessing that's what I press when I want to return to X0 Y0 Z0 that I've set? It's not working.

Thanks!

3:
Taig Micro Mill. 1/4-20" lead screw. Powered by 1.25hp router with a 4:1 pulley reduction. Driven by Ethernet SmoothStepper to a Gecko 6540. Nema 23 motors. 3 Axis.
Re: SmoothStepper Motor Steps Per Unit
« Reply #7 on: January 14, 2019, 03:14:01 PM »
Hi,
can't answer 1). It sounds to me like the jerk caused by taking a small step is flexing the machine. The spring back
you are observing is just that...the spring of the machine.

2) To my knowledge Mach does not have backlash compensation, it MUST be enacted it real-time and therefore is
SOLEY the responsibility of the ESS.

Please double check which of the two plugins  (Control vs ESS) the settings appear.

Craig
My wife left with my best friend...
     and I miss him!
Re: SmoothStepper Motor Steps Per Unit
« Reply #8 on: January 14, 2019, 03:17:38 PM »
Hi,
had a thought about question 3). I don't think its got anything to do with Demo mode.

Hit the <GoTo Work Zero> button and have a look at the status message in the lower left of the screen.
What does it say?

Craig
My wife left with my best friend...
     and I miss him!
Re: SmoothStepper Motor Steps Per Unit
« Reply #9 on: January 15, 2019, 11:32:50 AM »
status message in the lower left of the screen.
What does it say?

Status message says: Axis 3 commanded while disabled..

Also, I did some more testing and I don't think the machine is flexing. It's very rigid. I noticed that when I very quickly tap the jog key the motor rolls forward and then right back into the samp position. It looks like it's the motor itself doing the bouncing motion. Is this just because I'm tapping the key so fast something isn't registering?
Taig Micro Mill. 1/4-20" lead screw. Powered by 1.25hp router with a 4:1 pulley reduction. Driven by Ethernet SmoothStepper to a Gecko 6540. Nema 23 motors. 3 Axis.