Adding Limit Switches to my Gatton CNC

[@thomasgrim1549]

Mark, you never mentioned what you did with the shields. Shielding only works well if the shield is grounded at one end. If it is floating, it does not provide protection. If it is grounded at both ends, you get ground loops and a new source of noise in your system. I would consider connecting all the shields together at the ground bus point you've extended to the terminal strip.

[@MarkLindsayCNC]

You're absolutely right, Thomas. In fact, I forgot to mention a couple of things - like the switch mounts themselves. I'll address them all in the next video, before I get into the Mach3 settings. I have the footage, it just somehow got left out of the edit. Oops? Yeah, that's it. Oops.

[@jeffconner3412]

Thomas, wouldn't you ground the shields to an earth ground instead of the ground bus point. You are correct about not grounding both ends of the shielding. I have come across instances where someone has grounded both ends. The machine was not working properly until I disconnected one end of the shielding.

[@MarkLindsayCNC]

After reading a bunch about it, grounding the shield to the terminal block should do just fine. We're not dealing with huge voltages. We're dissipating RF as it comes in - if it should come in. And yeah, connecting both ends of the shield cable creates a ground loop.

[@andirachmatmulya2818]

Dear Mark and Thomas, I Found 4 core (conductor) cable with ground sorounding that conductor, is it mean shielded cable also ? If not, it can give protection from noise or not?

[@thomasgrim1549]

@@andirachmatmulya2818 A shield may be a braided set of wires that encloses the other conductors or a foil wrap with a bare wire in it that encloses them. Either one will work in this application. The important thing is that you should connect only one end of the shield, at a common ground point.

[@orlandi55]

Mark, thank you for explaining the why's too it helps a lot for a beginner like me.

[@timhalcomb4041]

Really enjoyed you taking us along on this

[@jaredhildabrant13]

Great video. Great explanation, very easy to understand. You are a good teacher.

[@TrevorsWoodShop]

You make it look easy Mark! Thanks for the video it cleared up a lot of questions I had

[@MarkLindsayCNC]

Thanks, Trevor! It's not super difficult, but there are some things to watch out for. I'm just trying to put info from about 5 different sources into one place. Hopefully it helps folks out.

[@whiteknight5951]

Glad to see that I'm not the only one not to stick to a strict color code. Sometime the limit of wire makes a difference when you try to save a few cents.

[@MarkLindsayCNC]

Another limit of wire is not being able to get your hands on it locally and having to wait 5 days to get it. Who would have thought that 6 more feet of wire would have been the difference? Sometimes you just gotta do what you gotta do. Thanks for watching!

[@whiteknight5951]

Luck on that, we have a lot of electrical supply houses near by to get wire from.

[@MarkLindsayCNC]

I live in a small town with a couple of electrical supply shops, but none of them had the stranded wire I needed. The wire I got first was supposed to be stranded, shielded cable, but as you saw in the video, it wasn't. And of course they won't take wire sold by the foot back, so yeah...

[@whiteknight5951]

Well, great job on your machine and the videos too.

[@MegaTopdogs]

Great video Mark well explained thanks

[@cncnutz]

Great explanation. It will be interesting to know your thoughts on using the machine with switches having come from a machine with none. Cheers Peter

[@MarkLindsayCNC]

Thank you, Peter. I'll most certainly talk about that in the next video. Spoiler alert - I haven't even started cutting projects yet, and I already like them.

[@OldEnglishWorkshop]

Great video as usual, looking good.

[@leroyscncwoodworx841]

Looking good Mark! Just an FYI Make sure you have your Mach3 software set up properly before you press the home button. I am speaking from experience, i had X axis homing negative and A axis homing postive. Not to good on the gantry.

[@MarkLindsayCNC]

I'm way ahead of you LeRoy, but thanks. I WILL be talking about that in the next video, because it may be the single most important configuration setting in this whole deal.

[@davesdrone3125]

Do you have any knowledge on wiring home/limit switches when using an optoisolated BOB, that you are willing to share?

[@andreww6738]

Hey there Mark, its been a while, I've been crazy busy working. Just watched this limit switch video. Excellent tutorial as always, this is what I am currently doing with my "ShoeString" CNC, so how perfect is that? Thanks. I appreciate the comments about the shielded cable, so I need to change that and will also put in the wire block on the underside of the table. Hope your doing well? Andrew Wright

[@MarkLindsayCNC]

Howdy, Andrew! I went with the terminal block because I had a lot of negative wires to run into a place that wouldn't accommodate them. It's not completely necessary. Also, the only reason I put that terminal block where I put it was because I have negative cables coming in from several directions, and that location was central to all of them. I could have just as easily mounted it on the back of my drive box enclosure. The location I chose just saved me a bit of wire, and solved a couple of routing problems for me. Good luck with your installation!

[@dindodayrit1834]

hi mark once again nice presentation which help me in setting up my cnc limit switched and understood the difference between using normally open and normally close switch. may i ask did you used all the same normally close switch to all axis. because the machine delivered to me when i checked it. i have my X AND Y HOME NORMALLY OPEN AND X HOME IS NORMALLY CLOSE. also my Y+ AND Z+ IS NORMALLY OPEN AND MY X+ IS NORMALLY CLOSE.

[@print3dsignal427]

Hey Mark I have built a Sidewinder CNC awhile ago and I’m planing to add limit switches to it. I’m curious what breakout board you have in your video I can’t seem to find one like it anywhere.

[@MarkLindsayCNC]

Jeff at Xylotex discontinued that breakout board about a year ago (just after I released that video, naturally.) I asked him what folks should look for when searching for a BoB, and he said to search for "D-SUB-DB25-Male-Female-Header-Breakout-Board-Terminal-Block-Connector". (Without the quotes.) For example, here's one on the unnamed auction site: ebay.to/2EnkIFW

[@print3dsignal427]

Thanks Mark. I used the suggested board and your video now I have limit switches on my machine, no more crashing. Now to see what else I can do with my new BoB.

[@dwightbennett3548]

What type of breakout board are you using?

[@MarkLindsayCNC]

I'm using an old-style pass-through parallel port breakout board. The board I have is no longer available, so I can't link it to you. Sorry.

[@dwightbennett3548]

@@MarkLindsayCNC Thank you