[Mr.Chips]

Steps Per Unit” in “Axis Calibration: 9/2/2008

Am in the process of fine tuning my CNC and have hit a snag while setting my “Steps Per Unit” in “Axis Calibration”.

Prior to any tweaking, I noticed in Motor Tuning the Steps per Unit was showing 2000. I am using a 10 TPI Acme so this sounds correct.

I have been air cutting and using a pen to draw the various Gcode files, everything was repeating and running smoothly except that everything was half size. Sounds like I need to adjust the Steps Per Unit.

I went into the Settings Tab and selected “Steps Per Unit” in “Axis Calibration” then the X axis, deleted the 0 and input 2”. Ran that and measured and it was 1”, input that figure and saved it. Did the same I think for the Z axis.

Went back to the Motor Tuning the Steps per Unit was still showing 2000. Hmmmm Thought this should be a different number now after what I did above.

Tried a X axis manual jog and the stepper makes about one revolution and stops, and buzzes. It does this in both directions. It does this every time I press X jog.

Tried Z axis manual jog and it moves just fine in the up direction but only about 1 turn in the down direction every time I hit jog.

Any Ideas?

[ger21]

What microstep setting are you using? 2000 steps/inch would be for full step. 1/2 step would be 4000, 1/4 step 8000, 1/8 step 16000.

Someone else reported problems last week with the axis calibration. I'd recommend not using it if it's not working correctly. Perhaps it's changing the steps/unit, but they're not displaying properly?? Not sure, but when you change the steps/unit, you need to re-tune the motors. That might be the problem. Try entering the correct number in the motor tuning screen, then save, close Mach, restart, retune, close mach, restart. See if that works.

[Mr.Chips]

What microstep setting are you using? 2000 steps/inch would be for full step. 1/2 step would be 4000, 1/4 step 8000, 1/8 step 16000.

Someone else reported problems last week with the axis calibration. I'd recommend not using it if it's not working correctly. Perhaps it's changing the steps/unit, but they're not displaying properly?? Not sure, but when you change the steps/unit, you need to re-tune the motors. That might be the problem. Try entering the correct number in the motor tuning screen, then save, close Mach, restart, retune, close mach, restart. See if that works.

Thanks
I verified that all of my step adjustable driver cards are still in the full step mode.

I tried deleting the 2000 steps per unit in the motor tuning utility and inputting 2000 and saving after each axis then exiting Mach 3 and coming back in, did this three times as you suggested.

The X and Y axis steppers are only doing couple of revolutions each time i press and hold the jpg buttons.
The Z stepper rotates a few revolutions in the up direction but only about 1 turn in the down direction every time I hit and hold the jog button.

Loaded a 10" circle Gcode and hit run, it moved slightly then all axis stopped and steppers buzzed. Naturally I stopped it.

Confused? ?

[Mr.Chips]

I went to the Diag screen and hit XYZ ref and all three axis move slowly tword home.

I think it has something to do with the “Steps Per Unit” in “Axis Calibration” utility.

Would it do any good to delete and reload Mach3?

Or would I get into more trouble setting it up again to this level??

Thanks

[Mr.Chips]

In Motor Tuning I slowed all the axis down to 10 IPM. and they all ran without any stalling but naturally slowly. Gave a X2" command and it moved 2" not half the amount it was doing. This is wierd before it would only move half of what i input.

I went back to Motor Tuning and changed the Y axis back to 40 where i normally run it. It moved + and - without any stalling.

I then Increased the Y IPM to 100 and it still moved + and - without any stalling.

This is strange, what effect would slowing the IPM from 40 (where it all of the sudden was stalling)down to 10 where it runs smooth and then back to 40 and then to 100 and it still runs smoothly. I didn't change anything else other than Motor Tuning.

[ger21]

Why are you running your drives in full step mode? You might find they run smoother and faster in 1/8 step mode. Also, try leaving the speed at 40 and lowering the accel. Does that help?

Reinstalling might be a good idea. You can back up your settings by copying the Mach3mill.xml file somewhere else before uninstalling. After uninstall, reboot, then reinstall, then reboot. Then, copy the backup .xml file back into the Mach3 folder, which should restore al your settings. If that doesn't help, you might want to delete the .xml file and reset everything from scratch. It's possible that the .xml file could become corrupted.

[Mr.Chips]

Why are you running your drives in full step mode? You might find they run smoother and faster in 1/8 step mode. Also, try leaving the speed at 40 and lowering the accel. Does that help?

Reinstalling might be a good idea. You can back up your settings by copying the Mach3mill.xml file somewhere else before uninstalling. After uninstall, reboot, then reinstall, then reboot. Then, copy the backup .xml file back into the Mach3 folder, which should restore al your settings. If that doesn't help, you might want to delete the .xml file and reset everything from scratch. It's possible that the .xml file could become corrupted.

Why are you running your drives in full step mode?
I didn't know any better. what are the pros and cons of the different step settings? My driver cards can go down to 1/16 step, I cut it down to 1/8 step and changed the step units to 32,000 but got about 1 1/4" on a 2" command. I will just adjust this by trial and error not the “Steps Per Unit” in “Axis Calibration”, afraid to try it again.

When I went down to 1/8 step the Y axis would only run at 60 IPM without stalling. Before it would run 100. I know speed is just bragging rights, I use it as a alignment and adjustment indicator.

I lowered the accel. from 32 to 20. Didn't notice any difference in air cutting.

If this all doesn't prove to be good then I'll consider a reload.

Thanks