[stk2008]

Hi all dont know if you remember me but I have been building a cnc mill for some time now and im so happy to say its very nearly done me workshop is 99% finished etc etc.

well today I have been wiring all the axis up X,Y,Z and they all work great woot now what worries me is the way I have wired the Estop i have wired it directly from the mains then into the psu`s it wors but is it right? ive read about back emf? but dont have a clue.

I would like to do it this way rather then just via break out board as that dont kill the power allso im stuck as to how to tell mach3 the Estop has been hit?.

heres me kit

bob
http://www.motioncontrolproducts.co....on-rev%201.pdf

drivers i think its these ones
http://www.motioncontrolproducts.co...._datasheet.pdf.

psu
http://www.motioncontrolproducts.com...plies_v2.0.pdf

please help me finalise this allso im running no fuses as of yet apart from the 13amp one in the wall where should i run fuses to keep me kit safe after befor the Estop directly from the mains supply?.

heres a layout of me wiring



im allso after wiring fans up but i have no power inputs for it should i just get another pc power supply and use that?.

cheers all.

[H.O]

Hi,
Most E-stop switches has two contact blocks. Usually one normally closed and one normally open but it can be two normally closed ones. You use the second switch wired between GND and an input on the break-out-board to tell Mach3 that there's an E-stop.

Normally it's not considered safe to wire the E-stop as you have done. It should not be enough to simply release the E-stop for the machine to start up. What you normally do is wire up a relay and a pushbutton so that the relay activates and latches with the press of the button. The E-stop switch is then wired in series so that power to the relay is cut off when E-stop is pressed. That way you have to release the E-stop and press the pushbutton to enable the system again.

/Henrik.

As for the fans, get two 24V fans and wire them in series across the 42V supply. That's proably cheaper than getting a separate supply just for the fans.

[stk2008]

hi thanks

my estop is a nc type just one input in and one input out.

its a puse to kill then has to be twisted to start again.
this is where i get lost with the relays could just take easy route and wire it directly to bob hehe.

im still lost here im a complete noob on electrics.

[Al_The_Man]

I agree with Henrik as to either an auxilliary relay for E-stop or similar method, the other comment I would have is you show the 48v common going out to the steppers, is the to the case?
If the 48v is not at Earth potential, the bonding lines you show should go to the green earth star point.
Or if the 48v common is at ground potential then they should be bonded together.
There should also be a bonding conductor from Earth star point to all metallic parts of the machine, gantry, spindle motor etc.
Some switches have the ability to add another section, either N.O. or N.C.
Al.

[stk2008]

ummm im crap at this i dont know how to go about it then i will get a relay tomorrow i want to run two Estops in total but how do i go about telling mach 3 me Estop has been pressed? i cant just put a wire from me Estop as its gonna have 240v going though it?.

im going to every thing is earthed via mains earth from plug socket all going into a centre block so yes start config allso me stepper motors will be earthed into that block as well i have 5 core wire one is reserved to mount on motor and then back to earth in me case im using.

the driver boards are only earthed via the earth input i suppose i should earth the case aswell?.

i will just use a pc power supply to power me fans as i have loads of em kicking around so wont cost a thing.

so if i get one relay 240v what one in one out? after me Estops job done?.

i know theres loads of Questions here but im lost (tho i have done better than thought there spinning etc so not to bad).

cheers again all and al the man u helped me so much last time.

[stk2008]

ffs i wrote a whole reply it bloody froze and lost it all doh.

any way i will get a relay tomorrow do i just get one in one out and wire it after me Estops?.

allso how do i wire it to tell mach 3 its been hit surley not from same wire as estops its 240v going into an input pin on bob if i do that?.

i will just use a pc power supply i have loads kicking around so thats not a problem that way i have loads of other options like 12v 5v etc etc.

every thing is earthed via the socket in the wall all into a central block so yes start config my stepper motors are wired vi 5 core so one core is reserved for me earth back to earth block in me case.

i have not earthed the drivers only via the earth input connection i suppose i should earth the case itself to.

i know theres lots of questions here sorry

edit sorry about posts i had prob with connection

[stk2008]

ok ive been looking and dont know what relay to get hehe should i get a std one or an actual estop relay prob is there not to cheap ive looked here http://uk.rs-online.com/web/
but cant see what i want?.

im allso getting this http://uk.rs-online.com/web/search/s...duct&R=1983192 from here today so could get
a relay from there to would some very kind person show me the best one to use as im lost.

edit
well im lost i have no idea what relay to use and even why i need one heheh ive been all over oxford and no one can help they all sell electrical goods but dont know any more than me so thats helpfull.

im sorry to be rude but please could someone point me in the direction i need to go iv looked here
http://www.cnczone.com/forums/showth...+wiring&page=2

and have no idea what it all means. like i say i have it all working seems good just that i need an estop relay? and fuses befor the estop button to be safe?.

im in urgent need of advice as im waitin to order from rs and could get a relay from there if they aint to much.

what will this relay do and why do i need it if me estop works?.

cheers

[stk2008]

ok ive managed to get another estop twist to reset job and it has to inipendent switches in it so can i have one switch that kills the 240ac (why do i need a relay? honest question i rely dont know?) and the other i will wire to me inputs on me bob so mach3 knows its been hit so that way i have hardware and software estop correct????????????????????????????????.

edit
ok ive looked on rs and seen this

http://uk.rs-online.com/web/search/s...0552867#header

is the only reason i need a relay is to force me to press it after ive hit the estop so if i hit estop it goes

switch estop back on
hit button to charge relay then ood to go again?.

[Al_The_Man]

Alot of this was covered in a recent post here:
http://www.cnczone.com/forums/showthread.php?t=86633
You may get some insight from it, it is a rather long posting.
Al.

[H.O]

Yeah, the thread Al links to covers much of it.

As for the need for the relay, it's like I said before - it's not considered safe when the only action that is needed to restart the machine is to "release" the E-stop. You should "release" the E-stop and then enable or reset the system by pushing a button. It's not that your way doesn't "work" it's just that it's not a proper E-stop system. In the thread Al links to he has linked to a document handling a lot of details regarding proper E-stop systems, it's a good read. With that said you usually don't have to go the "whole nine yards" with "real" E-stop relays etc on a small machine with step motors.

Get a pushbutton rated for 240VAC, get a 3 or 4-pole relay with coil rated for 220-240AC, you don't need a big one like the OMRON G7 you linked to. Something like this one will do. Wire it up as in the attached schematic and you should be good to go.

Once you have that working you can use a third contact in the relay to switch an input on the BOB to let Mach3 know you have an E-stop.

Be VERY careful with this, if you're not sure what you're doin don't do it. ALWAYS unplug the system from the mains before working on it!

[Al_The_Man]

For safer operation you could always use the 24v power for the E-stop circuit, relay etc, the 24v would be powered up at switch on.
This is my preferred way.
A contact on the E-stop relay could also power down any spindle etc or other 24v powered devices.
This keeps 240v off any operator panel or any other outboard E-stop.
Most of the industry now uses 24vdc control.
Al.

[stk2008]

thank u so much that was very helpfull H.Q very helpfull.
now i realy understand why i need it i can now understand how and why to fit it to me machine great.

ive allready placed an order now with rs so wont get the relay from there but no big deal will get it from another place and get a button at the same time.

i have fitted another nc button in me estop and set it to pin 11 when i now hit the estop it kills the power dead and allso sends signal to mach3 im so chuffed ive got this far the machine is 99% done just bits and bobs now.

i will get a relay etc tomorrow.

p.s is it worth me fitting my limit switches to the relay to or just let mach3 sort it out for now?.

cheers again H.Q and Al the man i will post pics soon .

ive just seen your post al the man u say 24vdc where is the 24vdc you refer to do u mean purchase a different psu to power that side of it?.

[H.O]

I prefer 24VDC for the control voltage as well but I didn't see one in the original schematic.

That's the main reason to be extra careful with it, so again don't do anything if you're not sure why you're doing it and how it's supposed to work, take no chanses, keep everything tidy and well isolated. Make sure you can't accidently come in contact with anything live and make sure all metal parts are grounded.

Good luck!

[Al_The_Man]

I think this points out the fact it should be a general recommendation and criteria that all machine control be wired in low voltage, on these forums at least.
Particularly when there is probably a large proportion of hobbyists that have not come in contact with control wiring or electrical practices before.
Although STK may get it done and it works, there is still 240v control out on the machine that could pose a future danger.
I have had my share of 240v zaps in my younger days.
Al.

[stk2008]

damn Al the man bet that tingled a bit hehe.
well cheers all for the help i cant thank you all enough.

ive got me motors running a program on the bench and it realy is very rewarding they are noisy aswell not realy loud just whine different pitched whines at all kinda speeds.

ive got this coming

http://uk.rs-online.com/web/search/s...duct&R=4691105

so im going to be very busy fitting it all in this tomorrow and allso getting a relay and push button i will look into getting it to run at 24vdc in future

i want to hard wire the limit switches up via mach3/hard wired into the relay as i have a n/c and n/o switch desighn so thats possible just got to look into how.

any ways thanks all for the help.

[H.O]

If you're going to wire the limits in your E-stop chain, ie. in series with the E-stop switches then you REALLY should switch to 24VDC control voltage. You do NOT want 240VAC wires on the machine with sharp, hot chips and cables constantly moving and flexing - really.

Since this is a stepper machine you should be fine wiring the limits to the breakoutboard as it is highly unlikely that any fault will generate an axis runaway that only a hardware limit will stop.

[stk2008]

ok i will leave it as software limit switches cheers i was more leaning that way tbh but just a thought hehe.

well im so close im waiting for dhl to drop me case off and grease woot.

cheers again

[stk2008]

doh i was given the wrong advice from R.S and the case i got was not what i was told it would be oh well.

on another not my dads mate is a sparky and he says he can get a box with

estop,push button and the correct relay all in one unit so im going that way now will keep u all informed on this.

[stk2008]

hi all im trying to jump start a psu without using a mobo im going to use it to power just some fans in a case for me cnc parts.

ive managed to jump start it and it will just stop nearly straight away i put about two fans on it and jump start it it ges for longer but random times just stops wont go for more than 20seconds.

if i connect a hard drive or dvd drive it wont jump start at all the psu works/worked fine in the pc it came out of two days ago.

cheers in advance

[martinw]

Dear stk2008,

You mentioned fans a while back. Why not use 230v AC mains ones? That way you do not need to worry about a power supply.

Just a thought..

Best wishes,

Martin