Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: MechanoMan on March 08, 2015, 03:18:06 PM

Title: Auto-aligning gantry during homing.
Post by: MechanoMan on March 08, 2015, 03:18:06 PM
I have a wide gantry.  As is, when first powered up, the 2 rack & pinions won't be perfectly aligned.  That makes cutting a large square a slight parallelogram.  Both motors are "linked" inside Mach3 to step together, not in the hardware.

I do have precision-placed endstops.  Right now I just jog against them slowly until one motor stalls against the stop and allows the other to catch up and also strike and stall against the endstop.  The grinding sound of a stalling stepped attracts a lot of attention... "no guys, it's supposed to do that."

OK so I need homing switches on both sides.  Is there a method inside Mach3 (or someone's Plugin) to home by driving until one motor or the other hits the home, stopping that specific motor, unlinking the drives, and driving the other motor (whichever one it may be) forward until it, too, hits the homing switch?



Title: Re: Auto-aligning gantry during homing.
Post by: ger21 on March 08, 2015, 03:25:59 PM
Yes, just install a homing switch and assign it to each motor.

When you say "linked", I'm assuming you mean "Slaved"?

The only thing you need to do besides enabling the switches is to go to Config >General Config and make sure "Home Slave with Master" is NOT checked.
Title: Re: Auto-aligning gantry during homing.
Post by: MechanoMan on March 08, 2015, 04:10:01 PM
Yep, "slaved".  I knew "linked" didn't sound right.

So then it temporarily "unslaves" them for homing, but steps them in sync until one of the motors finds its home?
Title: Re: Auto-aligning gantry during homing.
Post by: ger21 on March 08, 2015, 04:25:12 PM
yes
Title: Re: Auto-aligning gantry during homing.
Post by: derek on March 09, 2015, 06:21:06 AM
Make sure one of your switches is easily and accurately adjustable. There is no provision in mach to electronically offset the switches.