config two motor on gantry axis (Y) to square the machine

andypugh wrote: You could (with the correct HAL and INI config) use only two input pins for X, Y1, Y2 and Z. But Y1 and Y2 need to be different pins.

does this look right for the HAL pin assignment, for a XYYZZ machine?

net both-home-x joint.0.home-sw-in <= parport.1.pin-11-in-not
net both-home-y1 joint.1.home-sw-in <= parport.1.pin-11-in-not
net both-home-y2 joint.2.home-sw-in <= parport.1.pin-12-in-not
net both-home-z1 joint.3.home-sw-in <= parport.1.pin-12-in-not
net both-home-z2 joint.4.home-sw-in <= parport.1.pin-11-in-not

That looks about right.
You will need INI file entries setting for HOME_IS_SHARED and HOME_IGNORE_LIMITS

linuxcnc.org/docs/2.8/html/config/ini-co...t__lt_num_gt_section

Even then you _might_ need some HAL magic to prevent a limit-switch event from joint 1 and 4 when joint 0 is homing.

I am in the process of a cnc build, how is the gantry checked for square with a dual motored axis, Is there a routine in linuxcnc to use a probe to self check its alignment and restore the offsets or is it a manual process by checking with dti. Also I plan to put dual linear scale on the dual axis so can these be used to verify the gantry's squareness.

Hello ianlowe

Have you made any progress with the picture for aligning a whole or have you even finished it?

I also have a ganty with dimensions x 2500mm and y 1200 mm
How do you align yours ?

Hi MGM
I haven't got a satisfactory solution to a duel motor gantry yet, and I'm not quite at the point with my build when I will definitely need it, still a bit of hardware to build yet. I just tried to get information up front but some things are hard to find. Once I have a solution I will put comments on here if it will help others.

What seems to be the issue?
Tandem axis / gantry squaring is fairly easy since 2.8 and the changes made by Chris to PncConf if you are using mesa cards.
Not sure about StepConf though as i mostly edit files manually .