Micromill limit switch question

[milton d]

My 1996 Micromill with Smartstep/3 controller has 1 limit switch per axis. How can that be of any use other than in the one direction that the switch is operated? I'm sure there must be something I'm missing.

[angel-tech]

looking at the schematic for the micromill, the microswitches are used as the home switches. The axis movements are then limited the other end by softlimits within the software.

[milton d]

OK thanks, that makes sense. I'm not sure if TurboCNC has a limits function...I'll have to do a bit'o readin'.

[angel-tech]

are you running the machine on denford software or converting it to another method of control.

[milton d]

Yes, I had to remove the Denford top board from the controller and switched over to parallel port contol with TurboCNC software. I never got anywhere with serial/Fanuc. It was driving me nuts.

[angel-tech]

I've had a nose at the turbocnc manual, and it doesn't look like it has a softlimit feature, but you can use the switches as home switches. One way round this is to use Mach3, which will give you a far better interface and it's windows based rather than dos based.

[milton d]

Thanks! I hope to get Mach at some point but my funds are extremely limited. I know I can get a free demo version but the other problem is my selection of PC's is pretty limited as well. My shop computer is a PIII 800 mhz running W2000, well below Mach's minimum spec.

I have a homemade CNC router that doesn't have limit switches either. I've never crashed it (knock wood) in the 12 yrs. I've been running it. As long as I place my parts properly on the virtual machine table I drew up in CAD and always run an onscreen simulation before making chips, it's OK.

[angel-tech]

you don't have to have soft limits or limit switches, but it does help your peace of mind. You could add extra limit switches to the three axis and then you'll be fine.