Step through program with MPG

Hi
I am currently building a plasma cutter, and would love to be able to use a mpg to step forward and backward through a gcode file, using the increments set for the mpg.
My thinking is that if I have a mishap, and need to go back to a point in the program where it stopped cutting, I could simply step throught the program with the mpg to find the exact point I want. Being able to step forwards and backwards would be fantastic.

So my first question is... Is this remotly possible with LinuxCNC? If so, where should I start my search for info.

Regards

Andrew

There is a branch that allows forward and backward gcode movement.
There is no way to directly use an MPG to step through line-per-click.
You could probably rig something up to get close to that though.

I think the branch is reverse run _ I'm sure Rod will chime in soon - he is up on plasma code.

Chris M

cmorley wrote:

I think the branch is reverse run _ I'm sure Rod will chime in soon - he is up on plasma code.

Chris M

If you insist. There is a branch called reverse run that is pretty old and has fallen behind. But PhilC has his own branch that includes the reverse run branch with a current master branch build and a working plasma config on this thread.
forum.linuxcnc.org/plasma-laser/35449-another-plasma-component
I'm not sure how Phill has configured the reverse run to step backwards in the file but Skunkworks (I think) has an example of using the Reverse run branch with a MPG in this video that is doing exactly what you want.



I think you just need to map the MPG count to the reverse run count in Hal somehow.

Thanks Chris & Rod. Exactly what I was looking for.