Brother TC-225 / TC-229 adventure!

In that case using the W axis to command an offset component added to the joint.2.motor-pos-cmd, might be just the ticket. It would still allow the Z axis to use it's soft limits to keep it out of the restricted zone. A little logic could probably make W remain 0 at all times except during tool changes. W commands could then be used for all the tool change movements. The same could also be done just by sending commands directly to the offset component, but properly controlling the motion of the tool change moves (accelerations and velocity) would be a little more complicated.

That looks like a single Z axis, but i might be wrong.
As far as i can see, the other Z axis ( or W in this case ) has only a strict move from-to with no servo controll needed. Go up-stop-wait-go down-done. Some more logic for checking if Z is homed and spindle stoped should do it.
Do not shoot me if i missed something !

not sure i get what ya mean.

of course its a single z. andys idea with the w, is similar to the idea of using a c axis to rigid tap. its the same axis, but hes using W to separate its function from the working z axis.

his idea might work, if it doesnt cause a conflict and can interpolate between the 2 stages of travel smoothly like a constant velocity move..

Why would having a pause at Z0 be a problem other than being slightly inefficient?

being slightly inefficient is a problem

its just about restoring its original function, speed, etc. if it can change tools in 2.8 seconds instead of 3.5, thats worth a little effort.

well, got me my mesa 7i77. machines arrive next wednesday (a bit late due to forklift availabilties).

this week im going to build up the pc and get linux installed and ready to configure.

i did learn a little more about the ATC. the carousel has a 4 bit absolute encoder - 4 optical switches that pass light through a wheel with coded holes on 4 tracks. theres a 5th track, that looks like a 50% duty cycle pulse, much like a standard encoder. i suspect this one is just to determine movement/speed, etc it looks single channel though, so not likely able to detect direction like quadrature can..

i assume it should be pretty easy for linux to read 4 inputs and then turn their binary values into a number right?