Jog-while-paused

Recently jog-while-paused popped up again on the LinuxCNC mailing list (this happens a lot, check the archives), so it seems like a good time to point out that not only does Machinekit contain jog-while-paused functionality, this feature was added to LinuxCNC by Michael Haberler before there was a Machinekit project at all.  If you're unfamiliar with the jog-while-paused feature, it allows you to pause a running gcode program, move the machine (perhaps to take a measurement, inspect the cut, or perhaps replace a tool) then resume program operation.

Since so many folks seem to want the feature, but almost no one is using it, what is needed to get jog-while-paused working?  First, you need to have the jog-while-paused code in your build.  With Machinekit, the feature is in all current packages, but with LinuxCNC you'll need to dig around for the proper branches (check the dev-list archives around the date of the video above, Oct. 2013).  This adds new offset pins to motion that provides for the jog-while-paused functionality.

The next piece is some HAL logic to drive the new pins.  There's a simulation example provided with Machinekit (the sim.axis.jog-while-paused9 configuration) which includes some custom UI and HAL code to get jog-while-paused working.

So...what's really missing is just some real-machine example configurations and perhaps a bit of a HOWTO with instructions on getting everything working.  If you've been itching for this feature, why not try out the simulation config.  If you like how it works, merge the jog-while-paused changes into your machine setup.  Remember to take notes and share your results.  Once a few brave souls blaze the trail, I'm sure lots more will follow, and this is a great way non-programmers can help out with the project.