I’m in the final stage of my LR3 build, cleaning up the wiring and installing the struts. Initially, I was going to mount my controller onto the gantry. I was just wondering about the option of mounting my control board under/on the side of the table instead of on the gantry. If I make extensions of the stepper/end-stop wires of ~15ft (maybe less), would there be signal loss using 22AWG wire? Is it possible? My table is large enough to cut 4’x7’ and I’ll have the vacuum hose hanging down to the hose mount from above along with the power cords. If it would work, then I may create extension wires and run them down with the vacuum hose, as well.
This was just a thought I had, and was wondering if you may or may not know if it would work (or not).
Thanks!
Longer wires or smaller diameter wires mean more resistance. That resistance means more voltage drop inside the cable. Since the steppers are driven with constant current, it can be a little confusing to figure out what the effects are.
Basically, holding still or moving slowly (most milling is done slowly), there won’t be any difference (seriously, when the power supply has met the current, it turns off, so it doesn’t make any difference). When moving faster, the steppers also drop the voltage. Once that voltage drop gets high enough, the current starts going down and the steppers will lose some torque. If that lost torque is more than the torque needed, the steppers will skip steps.
You can mitigate it with: a) thicker wires, b) milling slower, c) higher source voltage.
Personally, I would look for a way to keep the controller attached. Just because 30ish wires is more of a pain to manage than just 2-4. I attached my PSU to the table and attached the controller and driver on the back of the gantry.