Author Topic: Slave axis homing  (Read 4914 times)

pedio

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Slave axis homing
« on: September 13, 2015, 01:19:00 PM »
Steve - is there any update to add the slave axis homing to the PMDX SmartBOB anytime soon? I have a gantry style machine. Currently I do the homing dance:

Home the machine
Override the limits
Run the primary X axis into the stop
Slowly move the X slave to the stop
Move the machine back off of the home switch
Rehome the machine

Let me know,
Peter

Bob at PMDX

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Re: Slave axis homing
« Reply #1 on: September 15, 2015, 03:20:17 PM »
We are working on this, though it won't be in the next release (which will be available "real soon now").  In my best optimistic estimate, it is at least a few weeks away.

Bob
Engineering Hell: Everything's right and nothing works.
Bob's Corollary: If everything's right and nothing works, double check your assumptions.

pedio

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Re: Slave axis homing
« Reply #2 on: September 25, 2015, 08:50:29 PM »
Yeaaaaaa - I can't wait. Have you seen the plugin that decouples the slave axis, homes the A axis, and then recouples the slave axis. Interesting but I don't know if I trust it.

Peter

Ps. if you see the auto touch off working let me know. These two would make my life a lot nicer.

Bob at PMDX

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Re: Slave axis homing
« Reply #3 on: September 25, 2015, 11:47:13 PM »
Yeaaaaaa - I can't wait. Have you seen the plugin that decouples the slave axis, homes the A axis, and then recouples the slave axis. Interesting but I don't know if I trust it.
That is essentially how any gantry-squaring homing procedure works.  All motors on an axis are started at the same time and with the same motion profile (accel, max speed, etc.) so that the gantry doesn't become more skewed while searching for the home switches.  However, each motor stops when it hits its own home switch, regardless of whether the other motor is still moving.  Once each motor is positioned at an identical distance (possibly zero) from its own home switch, the motors are "re-coupled".  Usually this all happens in the plug-in or (more likely) in the motion device itself, and Mach4 is (again, "usually") never aware that the slaved motors have been effectively uncoupled and recoupled.

I think I remember seeing a thread somewhere (on the MachSupport forums?? I can't find it now) where someone had some Lua code that attempted to re-map the motors in and out of a slave axis configuration.

Bob
Engineering Hell: Everything's right and nothing works.
Bob's Corollary: If everything's right and nothing works, double check your assumptions.