Planet CNC controller and software

[Leadhead]

Limit switches are a personal thing. I have them on one machine but never use them as I do not trust their accuracy and thus the repeatability. So on my main machine I just use the "soft limits" as an idiot border, so to speak. I zero XY&Z independently each time. Or put a hard stop(s) on the bed if making multiples. If I need to home all, or home XY, or just Z the TNG buttons on the l/h side bar are efficient and effective.
So for my part, limit switches are not needed. I work perfectly well without them.

[Clive S]

To stop confusion. Limit switches and home switches are different things, homing switches need to be accurate and reliable. Limit switches do not need to be accurate.

But it is possible to use a home switch as a limit switch combined. In this case you can make the machine set the SOFT limits so when homed the machine knows where it is and thus should not crash at the other end.

[A_Camera]

To stop confusion. Limit switches and home switches are different things, homing switches need to be accurate and reliable. Limit switches do not need to be accurate.

But it is possible to use a home switch as a limit switch combined. In this case you can make the machine set the SOFT limits so when homed the machine knows where it is and thus should not crash at the other end.

Yes. And to make things even clearer, the difference between hitting the home switch and hitting the limit switch is that when the machine hits the home switch (soft or hard, makes no difference here), it decelerates in a controlled manner and not losing position. Limit switches are for safety reason, so when the limit switch is hit you want the machine to stop as fast as possible and don't care about losing position. After hitting the limit switch the machine must be homed again, or zeroed at the right position, whichever you prefer, otherwise you will not be able to continue the job.

Yes, soft limits CAN prevent you hitting the wrong end, but that assumes that the machine was homed initially when the machine is powered on and that the positions are still safe to use. This is not always the case, for example after stalling or some other error which can cause offset or lost or extra steps. Especially with my 3D printer, when I power it on all axis values are zero, regardless of where the extruder head is positioned, so hitting the wrong end is easy. Of course, this can be prevented through prohibiting any move except homing after power on, but since it is just a 3D printer, I don't care about that.