[rwskinner]

I'm curious, I've never set limit switches or proximity switches up like the CRP's where they are in the direct path of motion. I also generally leave enough room for some over-travel so if a rapid move gets out of bounds the machine will stop before it hits a hard stop. Although their kit looks mighty handy and simple to mount I'm a little reluctant to mount my sensors this way.

With the CRP mounting orientation, how likely is it you will hit a sensor or hard stop if running at rapid travel speeds? Is this an actual problem or am I thinking about it too hard?

Richard

[mactec54]

rwskinner

You are correct in your thinking, they should never be mounted in a way that they could get hit, Proximity or switches, should be mounted were they can not be damaged by any moving part of the machine, they are there for safety & homing, so should be mounted using a fail safe method

[ahren]

Personally, I prefer not to rely on sensors of any sort for machine safety -- I'll take a good hard stop any day, which is why we always recommend bumpers and physical hard stops. Our sensor kits are primarily for homing, but they also function as limits.

We designed our prox switch and bumper arrangement to create a cost-effective and easily adjustable stop system that fits into a minimal amount of area. While there are certainly other arrangements, with our machine kits most of these end up requiring longer sections of extrusion and steel to work properly, resulting in a more expensive and larger footprint overall machine.

The bumpers on our machine are there in the event of a crash, and with 8mm of sensing distance, the proximity switches are fairly well protected when recessed behind them. If you're concerned about it, you can drop a t-stud and nut in somewhere in the travel of the machine before the bumper and the sensor can still pick up the signal, but we really haven't had any issues with this arrangement. Most of our customers also use soft limits to avoid potential interactions with the either the hard stops or switches after homing, which is always a good idea.

Best regards,

Ahren
CNCRouterParts

[rwskinner]

Thanks Ahren. That makes sense and you're right, I have soft limits set for everything as well on my other machines and that would help.

Richard

[FoxCNC1]

while I don't have limit switches yet, I have set up soft limits from the get go.

[rwskinner]

Yes, the soft limits work like champ with the slow down zone.

I ran past the limits a couple of times and hit the bumpers and the proximity switches never were touched. Well, not "I" but Mach did.

Mach3 / ESS decided to do some weird things during homing. 99% it works fine and every once in awhile it will do something stupid.
I think I have it figured out. If you hit the reference all button, and it homes, then you do it again, it does funky stuff, but if you move away from the limits then it works fine.
It's like Mach gets a switch state then changes directions while the other axis is going the opposite direction and the gantry tries to do the splits.

As long as I move off the limit/homes switches some it eliminates that crazy stuff.

Good thing to do like Ahren said and put them far enough behind the bumpers they don't get clobbered.