Wiring Diagram check

[eurikain]

Hello people ! Thanks for your great input :) I will modify the diagrams according to your advices. I do however have a few comments to make:

Hi G,

Dude, how did you guess ?

I have had quick look and don't see why you have to put relays into the home and limits circuit. It only makes more to go wrong and a relay introduces a time delay which could vary if your relay goes sticky.

I see you have relays for the homes which you don't want to be using. Wire them striaght to the Inputs on the BOB. Relay for the Limits wired in series is ok.

I use relays for the limit switches because I got inspired from JAZZ's OSCAR WINNING diagram (http://www.mycncuk.com/threads/9268-...ndle-VFD/page5). Thanks to Graem I understand that the limit switches in series are go through a relay because my BOB can't take 24V input so it isolates the BOB from that circuit. JAZZ, why would you not do the same for the home switches ?

This will put your home positions as a variable rather than fixed reference point.

Is that an issue or a personal opinion ? I am new to CNC, I honestly don't know what's best. So you're saying I should just have all switches as limits instead of separating homes / limits ? The only advantage I really see from this (with my current CNC knowledge) is that it would free up one pin on my board to introduce a touch probe later on in the build.

Also, when you hit a limit you need to have an override switch to be able to jog off the switch. The buzzer reminds you to reset the override.

You will have to set Mach3 to Auto reset Limts so you can reset Mach and reverse off the switch. Other wise you'll need a limit Override switch. Either works fine but overide switch is safer.

True ! I didn't think about it but it makes obvious sense :) Otherwise the machine wouldn't be able to keep moving. I like the safe option. I can add this override to the control box. As for the buzzer, I think I get the idea ;)

6Pst relay - you can get 'em, but at an ouch price. you could do the same job with DP relays, just use the latching one to control the others, and you can have as many as you need.

Good to know :) I'm not sure what the difference is between PST relays and DP relays.

Have the E-stop relay turn off a Contactor for the higher power devices like VFD, WP and PSU. This will mean you can use lower rated E-stop relay with fewer contacts. Most Contactors also have an Aux relay contact for control Signals which you could use for the Enable relay. Contactor is much more suited to mains power than normal relay.

I just got inspired from your diagram, that's why I used relays on mine :) Or maybe DT relay it the other word for contactor ?

On the PSU drawing you have the signs transposed for the +ve and -ve on the outputs.

Good catch, fixed it :)

I would not use the 36V PS as it is overkill on the size and you are just bringing more complications in to the system.

That's right. I'll just order a 24V and 5V PSU. $25 total on AliExpress vs. 100 Euros here in Belgium (which are PSU provided from China.....) loool

If you are using 24V why not get 24V fans?

Because I have looooooots of 12V fans at reach for free :) Would be waste not using them :) I can try to find some, but I think that might be overkill as I have more than enough fans I think (4 total). Well, I hear you already "you never have enough fans" lol.

Yes you do need to ground each stepper shield at the star point.

How about the limit/home switches ?