Help for Mach newbie needed - Limit sw/Home

[cjchands]

Hello, I am in progress of finishing up hobbycnc board and looking for advice how to setup Limit switch/Home with MACH3.
I read in their manuals, but not quite sure how most people wire their limits.
Q1). With limited parellel terminal# 10, 11, 12, 13, 15 Home/Lim. How do you wire 6 limit sw and 3 homes?
Q2). Any suggestion or advice where can I find & what type for limit switch NO or NC that compatible with MACH (I found about 15bucks each in the industrial store which I think might not be the right type).
Thank you very much in advance for all the help that I can get.
Appreciate it.
Jeff

[diarmaid]

Im making up my HobbyCNC kit at the moment and am going to add in limit switches, but unfortunately can't offer any advice yet on how it's done.

However I have found suitable limit switches Im going to use and they're only €1.20c ($1.44c) each. $15 seems very expensive.

[Torchhead]

Simple. Wire each Home switch individually (XYZ and A if you need it). Wire the Limits in series using the NC (Normally closed) terminals in a daisy chain. Any swtich in the chain that opens opens the chain. Now use the last input to monitor the series limits but set it to trigger on the open event rather than closed in MACH. It works better (less chance of noise) if all of the switch inputs are opto isolated.

We have an adapter card for our Mini-IO product that passes the proper buffered step & direct signals from the PP directly via a DB 25 cable to the HobbyCNC card and has opto inputs for the five port one inputs you hook up directly to your swtiches. There is also an optional remote relay card that uses the remaining outputs and has the quick connects for the Home and limits as described.

Tom Caudle
www.CandCNC.com

[ger21]

Not sure how accurate they'd be for homing, but any cheap switch like these will work for limits. http://www.surpluscenter.com/item.as...tname=electric

Wire all the limits in series, NC, to one pin. Then wire each home switch to it's own pin. NC is better than NO because it will break the circuit if a wire breaks or comes loose.

[cjchands]

1. Both of your suggestions say that I should wire HOME separately. Could it be possible that I use ONLY 6 Limit Switch and use home X,Y,Z (3 axis) as the commons with 3 Limit Switch....then use MACH3 to setup the HOME that way???? (All NC of course).

2). Ger2, thanks for the link to surplus limit switch, I noticed that it is SPDT and you can wire either NC, or NO. I have never use one of this before, so any comment on how to wire? And if all limits connect in series, then simple SPST all in series work, correct?

[sdantonio]

Originally Posted by Torchhead Simple. Wire each Home switch individually (XYZ and A if you need it). Wire the Limits in series using the NC (Normally closed) terminals in a daisy chain. Any swtich in the chain that opens opens the chain. Now use the last input to monitor the series limits but set it to trigger on the open event rather than closed in MACH. It works better (less chance of noise) if all of the switch inputs are opto isolated. Tom Caudle www.CandCNC.com

Hi Tom,

Would a diagram be available for the electrically impaired amongst us?

Thanks
Steven