Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: needleworks on May 12, 2020, 02:17:22 AM

Title: Homing?Limits
Post by: needleworks on May 12, 2020, 02:17:22 AM
Hi guys, looking for a little advice regarding a Mach3 problem.

Today I was machining a part that was very close to being max size for my work envelope, the fact that I had clamped the workpiece slightly in the wrong place, meant that I had reached the limit of travel in the Y direction, and subsequently crashed the machine into my limit switch. Odd thing is that the machine didn't stop, it just kept going susequently ruining the part. After stopping the machine, I checked the switch by manually pressing the switch down, and --- nothing ! I then tried all the rest of the switches and found that none of them were working.

Now before I started this job, I did as I usually do, and hit "ref all home" which resulted in the machine going to the home positions, activating the switches and stopping. To me, this proves that all switches are working as home switches, but none are working as limit switches ?
As a rule, I never tend to hit limit switches so I have no idea how long the machine has been like this. I have never changed any settings in over a year, and everything else is running great.

Also, after this happened I tried the machine running UCCNC, and for some bizarre reason everything works perfect there, machine stops as soon as any limit switch is actvated, and this was set up using the Mach3 xml file. Am I missing a setting in Mach3, or have I unknowingly changed something that I am unaware of ?

Any help greatly appreciated.
Title: Re: Homing?Limits
Post by: needleworks on May 13, 2020, 04:25:34 PM
Anyone ?
Title: Re: Homing?Limits
Post by: Graham Waterworth on May 13, 2020, 04:33:20 PM
A picture of your ports and pins screen would be a good starting point
Title: Re: Homing?Limits
Post by: needleworks on May 14, 2020, 03:46:15 AM
A picture of your ports and pins screen would be a good starting point


Tried to add a picture but I can't figure out how to attach it ?
Title: Re: Homing?Limits
Post by: TPS on May 14, 2020, 03:48:13 AM
if you post a reply, below the Input window is a + sign for Attachments and other Options.
Title: Re: Homing?Limits
Post by: needleworks on May 14, 2020, 10:03:50 AM
if you post a reply, below the Input window is a + sign for Attachments and other Options.

Yeah I got to that part mate, I then clicked on "choose file"   I choose the file but I can't see how to insert it !
Title: Re: Homing?Limits
Post by: TPS on May 14, 2020, 01:46:02 PM
you do not have to insert it, just Chose the file and hit Post
Title: Re: Homing?Limits
Post by: needleworks on May 14, 2020, 04:25:24 PM
you do not have to insert it, just Chose the file and hit Post

Ok, let's try this then.


Title: Re: Homing?Limits
Post by: Graham Waterworth on May 14, 2020, 08:21:31 PM
Go to the diagnostics screen in mach3 and then press each limit switch in turn and see if you see the correct limit led change state on the screen.

Is there no z-- limit switch fitted?

Title: Re: Homing?Limits
Post by: needleworks on May 15, 2020, 02:34:30 AM
Go to the diagnostics screen in mach3 and then press each limit switch in turn and see if you see the correct limit led change state on the screen.

Is there no z-- limit switch fitted?


I tried that Graham, all the limits change state when the switches are activated and no, there is no Z-- switch.
Title: Re: Homing?Limits
Post by: TPS on May 15, 2020, 02:57:32 AM
Settings -> Override Limits  enabled maybe?
Title: Re: Homing?Limits
Post by: needleworks on May 15, 2020, 08:13:34 AM
Settings -> Override Limits  enabled maybe?
Yes mate, auto override limits is enabled and always has been. Changing it back still doesn't make any difference though.
Title: Re: Homing?Limits
Post by: needleworks on May 15, 2020, 09:26:11 AM
Panic over guys, I think I've got it sorted !!
Somehow the Z++ had manged to change itself from active low to active high, I have no idea how this happened or how long it has been like that but all my switches are now working again.
Title: Re: Homing?Limits
Post by: KnuckleDragger on May 18, 2020, 07:06:44 PM
I wonder if you considered soft limits. They have saved my butt so many times! Every time I ignored the warning I watched my job go to hell!!!
Title: Re: Homing?Limits
Post by: needleworks on May 22, 2020, 09:12:48 AM
I wonder if you considered soft limits. They have saved my butt so many times! Every time I ignored the warning I watched my job go to hell!!!


I have never used them mate, never found a need  (as long as my limit switches were operational)  :-\
Title: Re: Homing?Limits
Post by: KnuckleDragger on May 22, 2020, 02:39:28 PM
Glad to see you got it fixed. Just had a USB keyboard pull a real boner. Hit any key get the reference all home command. The machine takes off and homes, ruin a small job. Thought it was Mach 3 but noticed the shift lock light would not function, swapped junk keyboard for Logitech, and back on track.