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Author Topic: Homing and Squaring a Gantry  (Read 2212 times)

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Homing and Squaring a Gantry
« on: January 28, 2013, 10:04:48 PM »
I have a gantry based machine that has separate motors for each side of the gantry. I have separate limit switches for each axis and want to re-square the ganrty when referencing the machine. I am confused about how to set the "Home Slave with Master Axis" checkbox on the General Configuration tab. Here is what the Mach manual says:
"Home Slave with Master Axis, if checked, homes both motors of a master/slave pair at the same time. This will not do axis straightening, however."

When the gantry is moving to the limit switches, you must have both axes moving together otherwise that will rack the ganrty. So I assume the checkbox would need to be checked. But if checked, then the manual says that the axes won't be straightened. What am I missing?

Offline ger21

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Re: Homing and Squaring a Gantry
« Reply #1 on: January 28, 2013, 10:21:00 PM »
The box should be checked if  you only have one home switch. It keeps the motors slaved throughout the homing procedure. When not checked, both motors home independently (at the same time) to their own switches, which is how the squaring is achieved.
Gerry

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Re: Homing and Squaring a Gantry
« Reply #2 on: January 28, 2013, 10:50:35 PM »
That makes perfect sense. Thanks for the quick response.
Re: Homing and Squaring a Gantry
« Reply #3 on: January 30, 2013, 06:46:37 AM »
I have this working well to square the gantry but would like to ask if there is a way to stop the little "dance" that it seems to do.

Both move to home
one switch is hit
then the other side homes.

Is it possible to have

both move home
one hits a switch while the other keeps moving ?

I also found it hard to get my switches mounted perfectly so I decided to get it within 0.5mm of where it needed to be and then make the last adjustment with the following bit of vb.


DoOemButton(357)    'deslave axis

Code "G1 F100 A0.270"       '*Place offset here* max 0.5mm adjustment!!!!  Move A axis (slave) the distance to adjust squareness
While IsMoving
Sleep(25)
Wend

DoOemButton(358)    'slave axis