Disabling stepper motor

[nods221]

I have an acorn board running a diy cnc lathe build. It using some Chinese nema 34 closed loop stepper motors. What I like to be able to do is run the axises manually with a hand wheel while still getting position feedback to the controller. So my question is, is this even possible? How do I disable the holding power of the steppers?

[tblough]

With Acorn, you cannot manually drive an axis because there is no position feedback to the controller. You can use "fly by wire" and have manually turned encoders to drive the axis motors, but you'll need an Acorn6 to do this. The regular Acorn only has one encoder port.

[nods221]

Right, that makes sense. Is there a way to quickly disable the stepper motors, without killing power. I know I would not have position feedback anymore and the machine would lose its home position but that would still be useful to me.

[centroid467]

Assuming you have the Enable signals to the stepper drivers wired correctly and set to the correct polarity (Normally Open or Normally Closed), you could try issuing M93 with the MDI to disable the motors until the next time you command motion from CNC12.

From the main screen: F3 MDI -> type "M93" -> press Cycle Start.

You'll have to home it again before you try running any programs or expect the soft limits to be in the correct place but you already know that.

[nods221]

That should work, thanks.

[suntravel]

IMHO not a good idea.

It is no fun to crank manual with a stepper attached, lot of drag and if cranking fast it blocks.

There is no need to turn by hand if you have an WMPG or USB BOB

Drive by wire is much smoother, and One Shots or Intercon are faster anyway

Uwe