Newbie- Home Switch (Mechanical, Photo or Proximity)

[LaserImage]

Originally Posted by escott76 I would think you want independent homes, and tied together limits no?

No. It doesn't matter if you connect 3 separate switches to 3 inputs or all 3 to one input. Mach starts moving in the first axis and sets home when the switch opens, then it goes to the next, and then the third. Even with limit switches it won't matter - Mach stops all movement when a switch is opened, it doesn't matter which switch.

Gary

[HimyKabibble]

Originally Posted by escott76 I would think you want independent homes, and tied together limits no?

Nope. The way Mach works, it makes absolutely no difference. For both home switches and limits, all Mach knows is you're at a home/limit. It neither knows, nor cares, which one you're at. It homes one axis at a time, so it assumes when a home switch it triggered, it's the one for that axis (seems reasonable....). For limits, it doesn't care which one is hit, it simply STOPs. So, functionally, there is no advantage to running all the extra wires to make them separate.

Regards,
Ray L.

[mkenney]

Thanks again for all the info. I ordered some hall effect switches to try out. I really like the idea of them being so swarth resistant from the sound of it. My home switches are currently wired normally closed as is rcomended. This bit me a couple times recently after installing the flood coolant and not properly protecting the switches. Bad sounds when the switch stay closed while homing:-)

Thanks again for the help so far!

Mark [mkenney]

[mkenney]

Originally Posted by BobWarfield I was really impressed with the accuracy, low cost, and durability of Vince's proximity sensor setup: http://www.cnczone.com/forums/showth...846#post541846 Cheers, BW

I'm trying to wire this up now. Not getting the hall effect to do anything yet, but know I'm missing something. Looks real great, now to get it working!!

Mark [mkenney]

[mkenney]

I posted this question over in this forum:

http://www.cnczone.com/forums/showth...846#post541846

I'm trying this setup and struggling so far. I have the same sensor's and swear I thought I have things wired correctly, apperently not. I have +5v going to pin 1 (VDD), pin 2 to the input on the break out board and pin 3 goes to the ground. I have a 1k resitor between the +5v and the input on the breakout board. I wave different magnets different ways and get nothing. What am I doing wrong, been one of those days?

[cadmonkey]

I assume you're not really using application circuit 12.1 just what you have listed above correct? I would wire up the circuit in 12.1 exactly, hooking grounds to the ground on the BOB and the Vcc to the 5V on the BOB. Before hooking up the Vout to the BOB, do you have a multimeter or better yet a scope? Personally I test on a breadboard on the bench (electronics, not machining) before it goes near the controller.

[project5k]

this is something that i should really put some time into on my machine, as it sits now i have no limit switches, or home switches or anythg.. i have some of the little roller switches, but running full flood coolant makes me worrie about them...

I have a pile of home door and window alarm magnetic contatcs, i wonder if i could use thoes, cause i can seal them up, and then i dont have to worrie about the coolant getting in them...

one other thing to think about, if your using any kind of magnetic switching, watch your ferrous swarf.. it could build up on the magnets and cause problems...

[mkenney]

Originally Posted by cadmonkey I assume you're not really using application circuit 12.1 just what you have listed above correct? I would wire up the circuit in 12.1 exactly, hooking grounds to the ground on the BOB and the Vcc to the 5V on the BOB. Before hooking up the Vout to the BOB, do you have a multimeter or better yet a scope? Personally I test on a breadboard on the bench (electronics, not machining) before it goes near the controller.

Yep, just using what I listed. I ordered the 470pF capacitor that I did not have. Was trying to get away with just a pull up resitor as the orginal poster of this was able to do, not my luck I guess:-) I do have some breadboards and a multimeter and orginally bread boarded it and was never able to get any change in the output?? I assume when they say that the output is active low that it turns into a gorund when the hall effect sensor sees a magnetic field, is this correct?

Thanks for the help!

Mark [mkenney]

[HimyKabibble]

Originally Posted by project5k this is something that i should really put some time into on my machine, as it sits now i have no limit switches, or home switches or anythg.. i have some of the little roller switches, but running full flood coolant makes me worrie about them... I have a pile of home door and window alarm magnetic contatcs, i wonder if i could use thoes, cause i can seal them up, and then i dont have to worrie about the coolant getting in them... one other thing to think about, if your using any kind of magnetic switching, watch your ferrous swarf.. it could build up on the magnets and cause problems...

Standard roller micro switches will not last long in coolant, as they're not sealed, and will eventually get coolant inside and stop working reliably. The magnetic alarm switches will have very poor repeatability. They might work as crude limit switches, but I'd be amazed if they were sufficiently accurate and repeatable to be used as home switches. And, they are almost certainly not sealed either. Best bet is either optical switches, or good magnetic proximity switches. The latter is covered in another active thread in this forum right now.

Regards,
Ray L.

[mkenney]

Originally Posted by HimyKabibble The latter is covered in another active thread in this forum right now. Regards, Ray L.

Moved some info over to the other thread to try to combine. Torn as to which thread is better for other's to have this in. The other thread is the orginal but started with something totally different. The Subject line of this one will be easier to find for other's when working on limit switches. As stated in the other thread, I yield to the admins and others that know better to advise on what to do. My fault for asking the question in two places, I should know better...

Mark [mkenney]