Motion Limit Switches

fcwilt

Hi,

I imagine this has been discussed but I cannot find it.

Is there a way to place limit switches to "gracefully" stop motion instead of just slamming into the end of the travel for the rail/rod/whatever?

It would seem that triggers could be used but the only thing that would seem to work would be an emergency stop.

I was thinking of something less drastic.

Thanks.

Frederick

alankilian

@fcwilt Are you talking about if you have missed-steps and accidentally hit the hard-stop?

Because setting the axis limits should prevent you from hitting the end-of-travel on an axis when doing moves.

Unless I'm misunderstanding something. (I have a delta, so things may be different for other configurations.)

fcwilt

@alankilian said in Motion Limit Switches:

@fcwilt Are you talking about if you have missed-steps and accidentally hit the hard-stop?

Because setting the axis limits should prevent you from hitting the end-of-travel on an axis when doing moves.

Unless I'm misunderstanding something. (I have a delta, so things may be different for other configurations.)

I'm putting together a small CoreXY for a novice.

When a stepper runs an axis into the end of travel it can make a disturbing sound. I was hoping to make this printer more "user friendly" and prevent things like that from happening.

Yes the axis min/max will normally will deal with that but not in all conditions, like when the end user decides that overriding the limits with M564 sounds like fun

It may be pointless and there may be a better way but nothing ventured, nothing gained.

Ideally, I suppose, there would be "hard coded" inputs on the board for this sort of thing that no amount of mucking about in the config files could override.

Frederick

Phaedrux

@fcwilt said in Motion Limit Switches:

When a stepper runs an axis into the end of travel it can maker a disturbing sound. I was hoping to make this printer more "user friendly" and prevent things like that from happening.

Stall guard?

@fcwilt said in Motion Limit Switches:

like when the end user decides that overriding the limits with M564 sounds like fun

There's only so many guardrails we can put in place.

A Former User

@fcwilt

maybe consider a 2step approach:

my reasonable 5 cents for the 1st step:
consider "photo electric barrier" where the carriage can run through, build the rails and placement of senor in a way, that you can run safely 10-15mm over it before it hits something hard, that is way more then any physical switch will give you.

my freak-out suggestion (some irony in there maybe) for the 2nd step:
in addition to the above, place a switch/breaker that cuts stepper-power at the end (hahaha, would need homing afterwards of course, unless you build a closed-loop stepper) or use stallguard there for an errordetection

Hope you could laught at the 2nd as well a bit (and maybe found in the first something useful)

S1lencer

Hi, had the same question at some point where i was using swithes instead of the stallguard homing.

My approach was to use some kind of IR-Probe style switches witch would spit out an analog signal and would slow down the axis like in the z-Probing movement with davids IR-Probe but only for X and Y.

Dont know i that is possible though.