No unhoming after emergency-stop or limit-sw trigger

Hi everyone,

after pressing F1 (emer-stop) or a limit-sw trigger the machine is still homed.
The servos are disabled. Which leads to: servo-position is lost.
Now enabling the machine again by hitting F1 and F2, but the machine does not request homing.
=> homing is lost. And the machine keeps on going. ???

How can i unhome the machine in case of emer-stop?

I did try VOLATILE_HOME = 1 but no help.

Any ideas?
regards, Tom...

AXIS 2.9.0-pre0-1456-gdb3a15891

Have you considered NO_FORCE_HOMING

Tom858 wrote: after pressing F1 (emer-stop) or a limit-sw trigger the machine is still homed.
The servos are disabled. Which leads to: servo-position is lost.

Since i have never seen such an issue on many servo driven machines, i have to assume that there is something wrong with the e-stop and enable implementation and/or wiring.
Look at the DRO when hitting the e-stop or limits, if the numbers jump, it would be safe to assume the encoders are getting powered off and that is not good. The encoders should be on all the time the PC and/or LinuxCNC is on.
More info on how things are set up would help.

Mike_Eitel wrote: Have you considered NO_FORCE_HOMING

That is used to avoid homing the machine on LinuxCNC start, and as far as i know it can not be used on dual motor per axis setups.

Thank you for the quick reply.
NO_FORCE_HOMING is the opposite of what i need.

In fact VOLATILE_HOME = 1 is the solution.

It was my fault. Fingertrouble with different hal. files in my directory.

I am using tandem axis. Homing works a bit different. (I have X-axis in tandem.)
Y and Z axis can be homed seperatly.
X only by : home-all. There is no button in the GUI for home-x.
But this is not really a Problem.

Tom...

Actally i did not propose to set it Just consider / control that flag...

Hmm,
seems like the Problem is not yet solved.


VOLATILE_HOME = 1 forces the machine to unhome when manualy switched off ( F2 ).
Means the command is active working. And correct so far.

If a limit switch is trigger the machine, it switches off. But is still homed.
This is not correct.

Do you have any further ideas??

Tom...

I encountered the same problem.
My external Estop disables the servo drives through a saftey relay and triggers the Estop signal in Linuxcnc.
When I press the Estop during a program it seems like the program stops not as fast as the drives.
Therefore the GUI positions do not match the actual positions.

Volatile_Home works for my since Estop is the only condition which causes a difference, but I agree that a unintentional triggered limit should unhome the corresponding axis.
Is there a way to achieve this?

But now I have another problem.

I would like to add a door switch that triggers and Estop so nobody can access the machine while running. But the door switch will also be triggered when the machine is in idle and therefore I would have to home the machine every time the door has been opened.

Is there a way to unhome the axis only when the estop happened while an axis was moving?

For the door, it is better to use feed-inhibit or motion-is-enabled or machine-is-on, of the top of my head, as those do not require homing but should stop the machine.
E-stop should definitely not be used for it.