Control 6 axis and 5 axis cnc machines from a single computer

Wondering if anyone has any recommendations on how to control a 6 axis cnc machine and a 5 axis cnc machine from a single computer.

I am developing a cnc system that is comprised of a 6 axis machine and a 5 axis machine. It is not necessary for all 11 axes of the system to be synchronized, but the axes of each individual cnc machine (i.e. the 6 axis and 5 axis machines) do need to be synchronized. One machine will finish an operation before the other machine will be commanded to perform the next operation. The two machines do not need to operate simultaneously.

With Linuxcnc is it possible to control two cnc machines (one 6 axis and one 5 axis) from a single computer with two instances of Linuxcnc or would I need two computers with instances of Linuxcnc running and control with a third computer?

I have vague memories of this being discussed in the past, and it was concluded that you can't run multiple instances of LinuxCNC on the same machine. I can't remember why, but possibly something related to the shared memory of HAL.

However it feels like something that _ought_ to be possible.

This might be something that the Machinekit folks have looked at.

There are ways to link multiple instances of LinuxCNC on different CPUs to synchronize their separate operations.

The Machinekit folks did more work in this area, specifically for workcell-type operations.
Their docs are hard to find, but you might look to see what has been written down. (Machinekit is a fork of the LinuxCNC project done in Austria, mostly, and was focused on issues like multiple cooperating instances of g-code-controlled machines.)

Jon

It would be much more helpful to know what exactly is needed and what types of movements are required, what functions and how they interact.
I would venture a guess that some of the axis have to move from one point to another while some other axis do their thing, so that can be controlled by PWM and limit switches, leaving plenty of axis usable for full control.

This is for a custom hobby cnc prototype that I am developing.

Variable position control is needed on all axes. For the six axis machine, motor synchronization is required for all six axes. For the five axis machine, motor synchronization is required for three of the axes. The other two axes of the five axis machine can operate without synchronization but will need to sequenced with the other axis movements.

andypugh wrote: I have vague memories of this being discussed in the past, and it was concluded that you can't run multiple instances of LinuxCNC on the same machine. I can't remember why, but possibly something related to the shared memory of HAL.

However it feels like something that _ought_ to be possible.

This might be something that the Machinekit folks have looked at.

Pretty sure Michael H had a branch that allowed multiple instances of linuxcnc.
probably related to his jog while paused work.

unfortunately it's probably all lost work at this point. His public githubs don't seem to have his older - linuxcnc only work anymore.

Chris m

jpsol wrote: Variable position control is needed on all axes. For the six axis machine, motor synchronization is required for all six axes. For the five axis machine, motor synchronization is required for three of the axes. The other two axes of the five axis machine can operate without synchronization but will need to sequenced with the other axis movements.

That sounds like you could _just_ squeeze that in to one LinuxCNC instance.

Machine 1 has XYZABC axes and machine 2 uses UVW axes.
The other axes could make point-to-point moves controlled by limit3 components.
(Though _homing_ a limit3-controlled axis remains a challenge)