Good evening all,

I have a very confusing problem. When an M3 command is active, and I try to initiate a tool change, the tool change fails and I get the message "limit switch activated." Tool changing works fine any other time. At first I assumed it was a noise issue with the VFD- not so. I disconnected power to the VFD and the problem persists. I have a turret up/down switch, and a turret home switch, Port 2 pins 9 and 11 respectively. I then assumed maybe one of these port/pin assignments was shared with an M3 function, i.e. motor step/direction and CW/CCW outputs. They are not.

Any ideas as to what might be going on?

Thanks!
Kevin

Are you running any brains or plugins that may be interfering?
If you attach your xml I can look and see if I can find a config issue.
Hood

Don't know anything about brains, and I think the only plugin is the smoothstepper one. .xml attached.

Kevin

Xml seemed fine but didnt have a SS there when I tested so will have to remember to take one home tonight to test again.
Hood

If you issue a M5 before the tool change will it work?

Graham

As Graham says, it would seem logical that a tool change would be prohibited whilst the spindle is actually running. 

Tweakie.

As Graham says, it would seem logical that a tool change would be prohibited whilst the spindle is actually running. 

Tweakie.

No, it is definitely not that, or as  far as Mach is concerned,  as I never stop the spindle to tool change.
Hood

I was asking to see if there was some sort of interlock in the M3/4 that is cancelled in the M5

Graham

Not really sure what you are meaning Graham but I just tested on the lathe. I used the rear turret as it indexes one tool at a time so is slow. I had the spindle doing a M3 then called tool5 (it was on tool 1) and whilst the turret was indexing I called a M4 and then a M3 then M4 again and all was fine.
Hood

Yes, this is on a lathe. Issuing the M5 before tool changing allows it to work. Might there be something in the M3 macro causing the trouble?

Kevin