Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: DAlgie on August 11, 2006, 12:54:17 AM

Title: Inital reference points and limit switches
Post by: DAlgie on August 11, 2006, 12:54:17 AM

With my Mach3 driven lathe, I am still a bit in the dark about limit references. On power up, I set the limits on both axis, but my limits switches aren't perfect, and I get the odd change, nothing bad though, maybe .005". I haven't figured out yet if there is a way to power up the machine, set the limits, and have it not change any of the reference settings. With a lathe, with indexable tooling, you can pretty much set your tools, and never change the tool offsets again, save for wear or the odd mishap. If I power down the machine, I have no reason to manually move the saddle or crosslide, and make it a practice not to, so when it is powered up the next time it would make sense for the control to just store the last position and go with that. I agree that you still should set limits in case the saddle, etc. has been moved while the control was off somehow, but the limits setting procedure should not alter the machine's absolute position. This then nulifys the inaccuracies of the limit switches.

Title: Re: Inital reference points and limit switches
Post by: Brian Barker on August 12, 2006, 08:59:19 AM

If you take a skim cut and type that value into the Xdro and press enter this will sift all tools to the right DIA :) this should help you...

Title: Re: Inital reference points and limit switches
Post by: DAlgie on August 12, 2006, 12:04:32 PM

Well, I've been doing that, but it seems that I have to do it everytime, I'll look into it more and report back, thanks Brian.

Title: Re: Inital reference points and limit switches
Post by: DAlgie on August 14, 2006, 01:38:12 AM

I did some checking tonight with dial guages set and setting limits on start up, a couple of other things, and the control does use the limit switches for setting it's position each time. I can take a skim cut each time also, but feel that you shouldn't really need to do this. I would like to use the limit switches just for that purpose; limit switches, not absolute position switches, but it would take the control to store and reload the absolute position last used on shut down each time, and ignore the limit switch signal, only use it for the machine limit safety. Is this possible, or could it be done with a simple macro or something? Thanks, Dave.

Title: Re: Inital reference points and limit switches
Post by: Brian Barker on August 14, 2006, 08:07:37 AM

If you would like to do that.. Don' thave the sweitch setup to be a home switch :)

Title: Re: Inital reference points and limit switches
Post by: DAlgie on August 14, 2006, 12:40:38 PM

Ahh, this makes sense, I'll try that. Thanks Brian!