martyscncgarage wrote: ↑Tue Feb 16, 2021 7:10 pm
When using proximity sensors, the target should approach the face at a right angle, not directly to the sensor.
Not that this is your issue, but its not good practice to set the sensors up the way you did.
I would not have put Z on a movable object like the tailstock. I would have fixed it at the end of the bed with the target attached to the side of the apron so that when it approached the Z+ sensor, it would pass over its face. You can't effectively set and trust any soft limits on the machine with a moveable home switch.
If you take the X+ sensor and turn it 90 degrees so the cross slide passes in front of it, that would be much better.
I watch this thread with interest to see exactly what the issue is. I would have liked to see a video of the issue too.
Marty
You make a pertinent point about how to setup proximity sensors Marty, I can see what might happen if anything goes wrong. I'll put changing them on my (long) to do list.
Regarding the moveable tailstock switch, I did have it setup the way you describe, but thought I'd be clever and eliminate the possibility of crashing into the tailstock. In my defense, I haven't used soft limits previously, (should I?) but I can imagine that slight movements in the tailstock, could alter the machine's limits. Is that what you meant?
martyscncgarage wrote: ↑Tue Feb 16, 2021 5:40 pm
Yes, please follow this post: viewtopic.php?f=60&t=1043
Include a fresh current report.
Please take the time to do a video showing the machine its limit switch positions and the limit switch themselves and demonstrate your concerns/questions in the video. Upload to YouTube, mark it as unlisted and share the video link here.
It seems to be related to the G28 move, since I have searched the pawn-mm.gcode file and cant find a specific X movement past 25.4mm.
With my limited understanding of GCode, speaking in terms of machine co-ordinates, the machine is trying to move too close to the zero point for the X axis. I thought that machine zero should be just before the X+ limit is triggered and that all X moves in machine co-ordinates should be in a negative direction from zero? The X limit switch is triggering at, or, near to machine co-ordinate X0, so if I was able to set the machine to move home position, even as little as 0.1mm away from the home switches, I think my issue might be solved.
Another thing that I have just found out, is that if I run G28 from the MDI, it stops both axis at a machine co-ordinate -5.00mm, which is exactly where I set it to stop, with @cncnsw's advice. Yet when I run PAWN-MM.cnc, it hits the X limit at a machine co-ordinate of +3.083mm.
I'm afraid this doesn't make sense......
If you run it viewing the G code screen, rather than the run-time graphic screen, what does the distance-to-go DRO display say just after the move on line 34, "G0 X25.4 Z2.54 T0101", begins?
For this testing, you might try setting the G28 position to Z-20, X-20 or something similar, so that you have more time to see what is going on after it leaves the G28 position, before it gets to your travel limit.
Regarding Z axis home switches, limit switches, and tailstocks:
A common setup is to have a separate Z+ home switch, installed at a fixed location on the bed; and a Z+ limit switch mounted on the tailstock. They should be positioned so that, with the tailstock in its normal position at the end of the ways, the carriage trips the home switch before tripping the tailstock limit switch; but also so that it can still reach and trip the tailstock limit before bending or breaking anything, if it goes past the home switch.
With this setup, you are protected against crashing into the tailstock when the tailstock is advanced, because you will trip the limit switch first; but you still have repeatable homing off of a fixed switch. You do, of course, have to move the tailstock back to the end of the ways whenever you need to home the machine.
Just out of curiosity, what does your copy of PAWN-MM.cnc (which presumably has not been changed since it was installed with v4.63) say on Line 7 / N0001?
cncsnw wrote: ↑Tue Feb 16, 2021 9:39 pm
If you run it viewing the G code screen, rather than the run-time graphic screen, what does the distance-to-go DRO display say just after the move on line 34, "G0 X25.4 Z2.54 T0101", begins?
This is the Gcode screen when the X limit error occurs Cncnsw:
