Limit switch

[Holy1]

Hi Everyone, I have a quick question. I am printing a tall object and wondered if the upper limit switch is triggered will that kill the job? It will be very close.
Thanks

[Eaglezsoar]

If a limit switch is triggered, the triggering axis should be stopped effectively stopping the print. Not sure if it stops all the axis but missing one will certainly put a damper on things.

[Holy1]

Ok, so I answered my own question. The print did NOT stop when the limit switch was hit. Luckily I was on hand and to stop it. Could have been ugly.

[Eaglezsoar]

Ok, so I answered my own question. The print did NOT stop when the limit switch was hit. Luckily I was on hand and to stop it. Could have been ugly.

I am surprised, the firmware must be set to ignore limit switches which is surprising but also good to know.
Thanks for informing us, that kind of information is important. I am glad that you were watching it, you may be purchasing new belts or worse if you were not there.
If SeemeCNC staff is reading this perhaps they could explain why contact with the limit switch did not shut down the axis or the print. Perhaps I will send John an email
and ask him and report back his answer.

[Holy1]

The Quick Start Guide on the download page stated >>set the printable radius to 75 and the printable height to 250>>. 250 was the height I built my model. It should be 230 . I set it from the quick start guide instead of the manual. Live and learn.

[Nylocke]

I think I know why they set it up this way At the Detroit Makerfaire last year, Steve's printer was having issues, where the way he wired it the limit switch was getting triggered while printing because of EMF from the stepper. John decided he should exaggerate this issue by simply grabbing the switch and holding it down until the hot end crashed into Steve's candle holder he was printing. Steve then did some emergency rewiring and got his printer back up and running. They probably changed their standard after that incident

[Eaglezsoar]

I emailed John about how the limit switches are setup in the .091 Repetier firmware and am expecting a response soon.

[bvandiepenbos]

I had issues with one of my machine builds that we ran the stepper motor wires and end stop wires inside the same extrusion. Machine would randomly wig out (lose steps, prints shifting mid print, crashes, not homing properly, etc.) After much hair pulling we discovered the stepper motor wires caused interference in the end stop wiring. Changed wiring location and all was well.
btw, a flakey end stop switch can cause same random problems.
At that time the firmware was looking at end stop signal while printing. I think John may have changed firmware to not look at end stops after homing for that reason.
I can see that would not be ideal in the case of print height reaching mechanical limits.
Oly, if you read this can end stops be enabled so machine fails safely?


FWIW...
if you are really needing to maximize print height keep in mind that the print height max is not flat, it is more of a cone shape. For example, you can print a taller cone shaped object than you can a object that has a flat top.
when moving to extreme X & Y moves one truck goes much higher than the rest.
hope this makes sense, I don't know how to explain it very well.

[johnoly99]

It sure can!

ANd yes, i disabled it after homing to prevent any interference, but with routing the wires seperately, it's a non issue. I'll try and get that sorted out tomorrow.