Setting up a gantry with 4 joints and 3 axes

I have a gantry that I am trying to set up as a 4-joint, 3-axis machine so I'll be able to easily home and square the two motors on the Y axis. I've been scouring the documentation to try to figure this out and have run into a wall. I'm asking this on the stepconf section because I used that wizard to make my current profile, and hope I can use it for this change as I don't have experience editing config files directly.

I gather that I need to:
* upgrade my version, (but I can't tell to what version)
* start the new version of LinuxCNC, at which point a script should update my configuration to joints/axes format
* do some editing of the configuration to define and link the two Y-axis joints

So far I have updated to version 2.7.12 and 2.7.12-23-gade72db (with the AXIS interface). After booting both versions I checked my config directory and the .ini file was unchanged, which made me think the script hadn't updated for joints/axes mode.

QUESTIONS: Am I using the right version? If so, how do I get at the joints/axes functionality? Am I posting in the right forum section?

Thanks very much!

--Abe

The correct version for the updated gantry configuration is "Master" aka 2.8pre. It is unreleased and "caveat emptor" -- but several contributors are using it every day just fine.

I'd suggest you update as described here: forum.linuxcnc.org/9-installing-linuxcnc...l-current-master-2-8

Then read through a recent similar journey here: forum.linuxcnc.org/39-pncconf/34051-2-st...n-one-axis-5i25-7i76

That thread has specifics for a Mesa card and the associated config app, PNCConf instead of Stepconf -- but the outline of required file changes is the same. You create a 4-axis XYZA configuration in Stepconf, then make manual edits to convert the A axis to the 2nd "joint" of the combined Y-axis. All the details and caveats are in that discussion.

Thank you! I just installed 2.8pre and we'll see where that takes me...

Just be aware that as of 48 hours ago, master branch had a regression in the homing using the axis GUI. If its not working for you then change to the Gmocappy interface (which is editing one line in the ini file.)

I will post up a minimalist config I created for Chris Morley using Mesa hardware. Chris knows about it so I am hoping its been fixed by now. (but I compiled from source, so the deb install might lag behind this.)

Interesting you mentioned "one line" change to get Gmoccapy -- I tried that one change today (from a known-good Axis ini/hal combo) and it barked about around 20 missing items. I didn't track them all down, but I'll be trying again later this week.

I finally got a chance to try these suggestions, and now I have more questions!

DanMN:
Looking at the thread with chadrat6458, all I see in the INI file is that you moved the block for JOINT_3 up with JOINT_1, you changed two references of XYZA to XYZY, and you made sure the new Y joint was LINEAR, not ANGULAR. To configure my 2-Y-motor gantry, I also modified the .INI file with those three changes. Was there more I should have done? My INI file is attached.

I made no changes to my HAL file, which is also attached.

When I start LinuxCNC I can run the X and Z axes just fine, but only one motor runs on the Y axis. Also, the homing menu doesn't give me an option to home the Y axis.

Does anyone have a suggestion? As you can tell, I don't have a grasp of how the joints and axes are linked to each other in the INI file, and I wonder if that is the problem.

Thanks,
Abe