Gcode and hal pins values

Hi.

I've got an interesting task, to make something like smartprobe.ngc but without touch probe.

So the guy has machine with X linear and A rotary axis. Also there's Z axis without motor but with encoder. At the bottom of Z axis there's bearing which is riding on the object. And we want to get the table of encoder values at specified x and a.

So I thought of just logging (LOG, X#5420 A#5423 Z5422), but probably it'll raise FError because EMC2 will not touch Z axis but will see that it moving.

So is there any way to echo encoder.0.value via from Gcode (LOG, ....) or any other way?

Thanks a lot! M66 is excellent and easy way!

THC comp is interesting too but a little bit complex for newbie ... The guy who asked me how to do it is just taking his first steps with EMC2.