Electronics for New Machine + Chinese Spindle + VFD

[mturneruk]

Jazz

I now get your latching circuit now. Nice one.

I think you didn't quite understand what i was on about with the limits.

I DO want limit switches on all axis. It's easy to 'over jog' if your not careful.
I DON'T use soft limits. Well haven't up to now anyway.

I want 3 of my switches to double up as homing switches. Which i know how to setup in Mach3.

Just been looking at the KK01 breakout board wiring diagram (below) from CNC4YOU and it says you can use 24v with it for the limit switches as long as you add some 1.8K resistors.
Looks like i would have to add one in the Estop signal wire as well.

I think that would mean that I can do away with that second relay. I have modified your wiring diagram with what I think I can do.
See below. Make sense ?



I have made some more space in my enclosure. The 48V PSU now mounts on the outside of the enclosure back panel. I have made up a box with appropriate venting to enclose it. I even painted it the same colour. This will make a big difference to the space I have to play with inside.
I decided it was "Out of the box thinking". LOL

One other thing - been reading about relays and from what I can gather a 4PDT relay can be NC or NO depending on which terminals you wire to. Is that right ?

What u drinking - Guinness?

Thanks Jazz
Martin

[mturneruk]

Actually this is getting more complicated.
It looks like if you use that 24 volt input to the VCC in on the KK01 breakout board, you need to put resistors in the output to the drivers as well.
Think your relay idea might be simpler after all.

Would proximity switches be less prone to giving false readings?
And avoid the need for the relay?
And be more accurate ?
It looks like they are powered separately from the signal line.

Here's a link to the manual that shows the switch wiring.
http://cnc4you.co.uk/resources/KK01.pdf

Thanks
Martin

[Clive S]

Actually this is getting more complicated.
It looks like if you use that 24 volt input to the KK01, you need to put resistors in the output to the drivers as well.
Think your relay idea might be simpler after all.

Would proximity switches be better / simpler, and avoid the need for the relay?
It looks like they are powered separately from the signal line.

Here's a link to the manual that shows all this stuff..
http://cnc4you.co.uk/resources/KK01.pdf

Thanks
Martin

Martin The 24V line is only for the limits + estop. The driver signals are output from the BOB that will be 5V so no resistors needed.
.
The Estop line to the bob is at 5V as it is isolated by the contacts of the relay (ie fed from the BOB through the relay contacts and back to the BOB) .
.
If you go with sensors then you would not need the 24V SPST relay but then to be safe I would put a 1k resistor in the signal line ( usually black wire) to limit current.
.
Re the 4PDT relay it can be used as normally open or closed depending which contacts you use on the relay.

[mturneruk]

Thanks Clive.

Ok. have done some more reading on using 24v for limits.
I will stick with the relay as per Jazz's diagram.
I assume using prox sensors will make no difference in accuracy terms for homing as it's the relay that is causing the inaccuracy.
I can live with that.

Thanks.
Martin

[Clive S]

I have made some more space in my enclosure. The 48V PSU now mounts on the outside of the enclosure back panel. I have made up a box with appropriate venting to enclose it. I even painted it the same colour. This will make a big difference to the space I have to play with inside.
I decided it was "Out of the box thinking". LOL

Have you thought about taking the VFD out of the box instead of the 48V PS.

[mturneruk]

Yeah Clive. But it won't work so nicely.

This way the whole thing stays all as one unit with the controls for the VFD on the front.
I 3d printed the white cover, which when removed allows me to access the terminals without taking the box off completely.



Cheers
Martin

[JAZZCNC]

If your going to have Inaccurate home switches then there's no point having them at all really.! . . The whole point is accurecy and repeatabilty and you'll lose this thru a relay.

If the KK01 can accept 24V then it's simple just drop the relay and put resistor in series. It's the weak 5v signal that's the main issue so removing this removes the problems with sharing switches and complexity of using a relay.

If your planning on sharing switches for both then make it even simpler and make the Switches Travel with axis then sense adustable Targets at each end. This way only need 3 switches and one Input total.

Prox swithces are much better than Micro switches and cost about £1.50 so it's cheap as chips.!

[uli12us]

Where can I buy Prox switches for £1.50?

[JAZZCNC]

Where can I buy Prox switches for £1.50?

Well here's one £1.40 http://www.ebay.co.uk/itm/LJ12A3-4-Z...kAAOSwvt1WQ~SR

Look harder and you'll buy several of them working out at roughly £1

Here's the very switch I tested to show how well they work on a router.

[mturneruk]

Excellent. I like your idea that sounds better and much more accurate.
What confused me was this diagram in the KK01 manual showing that I might need to put extra resistors in the driver wiring as well if I was running 24v through the KK01.
That put me off.



Excuse me for being dumb again, what are the prox switches actually looking for - a magnet (target wise)?
I've looked and can't find any info.

Look what I got this afternoon - happy days!



My cousin cut them for me in his engineering shop.
The CNC mills he's got are serious.
They are perfect the bearings have dropped in beautifully.
So I can start building my machine now.

Thanks Jazz for your excellent input.
Martin