Parallel step/direction versus slaved drivers

[dbrownproto]

Hello,

I am working on converting a CNC router from NC Studio to Masso and I am trying to understand drive configurations.

If I have two stepper motors on an axis, why would I choose slaved drivers over paralleled step/direction pulses?

Thanks,

Dave Brown

 

[derekmccoy]

From what I ve learnt, unless you have servos (or closed loop steppers) and a rigid chasis, perpendicular axes can go out of square.
As an example this table I have here is so rigid, I can push on one end of the 3 metre gantry and the whole thing will move without locking up. So when it s powered off it kinda squares itself because the thing is so rigid, the pinions can t move a single tooth on the rack without the other doing the same. It s also on servos so it shouldn t come off square even if it weren t rigid.

If you re running steppers that don t have encoder feedback to the drive, you kinda need the second drive on a slave axis so it can be squared when homing.

 

[breezy]

Dave,

As Derek has said if the gantry is stiff then parallel electrical signals is all you need, but if the gantry can flex and the mechanical drive mechanism can be defeated, ie belt drive, then you need auto squaring which is what you get with software slaved drives. On homing the slaved axis is treated as two independent axes and MASSO drives each to their respective homing switch and backs off, there after it treats the two axes as one.

Regards,

Arie.

 

[dbrownproto]

Thank you for the responses, the Y axis on my machine is a 8 x 12 steel tube on linear ways. I think the axis remaining square should not be an issue.

Dave