Slaving the second gantry motor (7i92)

hm2_stepper is quite likely to "just work" with 3 motors, but it isn't set up for a gantry.

git.linuxcnc.org/gitweb?p=linuxcnc.git;a...ca2d40bb1de299885a9f

Alternatively you can bypass the PID in the your existing HAL file, set the stepgens to "p" not "v", connect stepgen,N.position-command to axis.N.motor-position-cmd and so on.

You probably need to learn to understand HAL files at some point anyway.

Or.. Tune the PID.

So you've given a .HAL file there. The .INI file contains a lot of PID-specific stuff. Is the .INI PID stuff totally ignored if the .HAL doesn't use it?

dannym wrote: The .INI file contains a lot of PID-specific stuff. Is the .INI PID stuff totally ignored if the .HAL doesn't use it?

Yes, the HAL file looks for things in the INI file, things it doesn't look for don't get found, but do no harm.

OK, good to know.

Your file used trivkins, not gantrykins. In truth all I need is this to act as a gantry and support independent homing of each side to ensure it will run squared. Is trivkins sufficient?

dannym wrote: Your file used trivkins, not gantrykins.

Yes, I did say that it was for a three-motor system rather than a gantry. But it isn't much to change to make it into a gantry.

andypugh wrote: One thing to be aware of is that LinuxCNC doesn't wait for the second axis to finish homing, so you need to configure so that the final rapid to home is as short as possible or you can have one axis doing a rapid one way while the other is doing a slow search in the other.

This is, admittedly, not ideal.

In this post:

Dual axis homing

Charles Steinkuehler appears to have gotten it working with Trivikins.