[bonmotwang]

I will try blue :-D


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[Mad Welder]

........Do you have any up to date pics on the electrical?......

My electrical setup is still a temporary setup eventhough I have the BOB's and power supplies mounted in a timber box , but as I'm using the mill during the build process I was waiting to finish the build before finally deciding what size of electrical box and where to mount it and watching and reading all the different build threads here too from you guy's I'm getting better ideas too

so as to answer your question the grounding solution worked for me but isn't my final setup...I used four core 4mm multi strand to power the motor from the VFD and the fourth wire (ground) I connected to the motor casing, then connected another ground to one of the screws and this to the spindle head then to the Z saddle and then to the Z column also I connected a ground from the VFD (power supplies terminals) to the bench.......

[Mad Welder]

What does you existing Y look like? :-D


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I had the Y axis motor mounted in the front initially




then changed to rear mount





before this final and last alteration the posts are here http://www.cnczone.com/forums/1074289-post108.html and here http://www.cnczone.com/forums/1075393-post112.html and then my final and last setup is the attached image below....

[FannBlade]

Thanks. Mine is done very similar.
I here alot of talk about the "dreaded" ground loop but still have no idea what that means.

see you have a network cable hooked to the VFD, will that plug in to the BOB and allow proper configuration?

[SCzEngrgGroup]

A ground loop is basically a ground path that is not intended to carry current, that, due to improper wiring, does end up carrying current. An example is the shield of a shielded cable. A cable shield should NEVER carry current, if it is to do its job properly. In fact, in most cases, only one end of the shield should be connected to anything, specifically to preclude it from ever carrying current. But if both ends are connected, and the two devices it is connecting are not properly grounded, current WILL flow through the shield, and this can easily induce noise in the conductors in the shielded cable. It is especially important that any high-current devices be very well grounded, and that all such devices are connected together ONLY at a single point, usually near the power source. One almost sure-fire way to create a ground loop is to daisy-chain power and ground connections from device to device, rather than running a separate wire from the power source to each device. Ground loops can create flaky problems that can be extremely difficult to track down and correct. Poor grounding practice is probably the single most common source of problems in home-built CNC machines.

Regards,
Ray L.

[Mad Welder]

...... see you have a network cable hooked to the VFD, will that plug in to the BOB and allow proper configuration?

no in my case the network cable is connected to a remote keypad which I bought with the VFD as I probably will mount the VFD out of reach, and to connect to the BOB I will use the buzz bar in the bottom front of the VFD face in the pic you can just see two red wires dangling where you have to connect to a switch....kinda held me up first and had to read through the wiring specs to understand it and it doesn't appear to be too daunting a project to connect to the BOB going by the specs but actually connecting it is a different matter

[FannBlade]

A ground loop is basically a ground path that is not intended to carry current, that, due to improper wiring, does end up carrying current. An example is the shield of a shielded cable. A cable shield should NEVER carry current, if it is to do its job properly. In fact, in most cases, only one end of the shield should be connected to anything, specifically to preclude it from ever carrying current. But if both ends are connected, and the two devices it is connecting are not properly grounded, current WILL flow through the shield, and this can easily induce noise in the conductors in the shielded cable. It is especially important that any high-current devices be very well grounded, and that all such devices are connected together ONLY at a single point, usually near the power source. One almost sure-fire way to create a ground loop is to daisy-chain power and ground connections from device to device, rather than running a separate wire from the power source to each device. Ground loops can create flaky problems that can be extremely difficult to track down and correct. Poor grounding practice is probably the single most common source of problems in home-built CNC machines.

Regards,
Ray L.

Thank You that makes more sense to me now.

no in my case the network cable is connected to a remote keypad which I bought with the VFD as I probably will mount the VFD out of reach, and to connect to the BOB I will use the buzz bar in the bottom front of the VFD face in the pic you can just see two red wires dangling where you have to connect to a switch....kinda held me up first and had to read through the wiring specs to understand it and it doesn't appear to be too daunting a project to connect to the BOB going by the specs but actually connecting it is a different matter

OK like mine with a removable control. Going to work on hooking up my VFD today

[Mad Welder]

...... It is especially important that any high-current devices be very well grounded, and that all such devices are connected together ONLY at a single point, usually near the power source......

Yeah all my stepper drivers and power supplies are connected individually and not daisy chained I had read that somewhere in my Keling pdf's, when I was wiring them first

Have I wired correctly my new grounding of the motor, spindle head, Z saddle and column?

[RTTIM]

Nice description Ray!

The two key things to take from what Ray said:

All grounds should tie together at one and only one point.

With shielded cables, the shield should be terminated to ground at only one end.

[Mad Welder]

Nice description Ray!

The two key things to take from what Ray said:

All grounds should tie together at one and only one point.

With shielded cables, the shield should be terminated to ground at only one end.

so rather than 'daisy chain' my grounds should I bring each and every ground back to 'one point'?

[RTTIM]

so rather than 'daisy chain' my grounds should I bring each and every ground back to 'one point'?

Ideally yes. The reason is that when you series ground everything, if something happens to the the ground somewhere along the line, everything downstream may be adversely affected. It also makes them more complex to troubleshoot.

By contrast if you wire in parallel, each circuit has it's own dedicated power and ground wires. If something goes wrong, only that circuit is affected. If it all comes back to a central point, it also makes it a lot easier to reconfigure things if need be.

[Mad Welder]

yeah that makes sense I'll rewire the machine and table grounds.

thanks again

[SCzEngrgGroup]

Ideally yes. The reason is that when you series ground everything, if something happens to the the ground somewhere along the line, everything downstream may be adversely affected. It also makes them more complex to troubleshoot.

By contrast if you wire in parallel, each circuit has it's own dedicated power and ground wires. If something goes wrong, only that circuit is affected. If it all comes back to a central point, it also makes it a lot easier to reconfigure things if need be.

Even if the wires remain intact, it still causes problems. Whenever current flows through a wire, there is some resistance, which means there is some voltage drop. The higher the current, and/or the longer the wire, the larger the voltage drop. Suppose you run a wire from your power supply, to the first motor controller. Then wire from there to the second motor controller, and from there to the their motor controller. The piece of wire between the supply and that first controller will see the current from all three controllers, so will have a hefty voltage drop. The second link will see the current from two controllers, and so have roughly two thirds the loss of the first one. The third link will have the least drop. But, the total drop seen by that third controller will be the total drop across all three wires, so it will always see a lower voltage than the other two controllers. And, when it's drawing max current, that will drop the voltage see by the other two controllers, so each controller makes noise that is injected into all other controllers. Not good! Wire them all separately, and all these problems all but vanish.

Regards,
Ray L.

[SCzEngrgGroup]

Here's a post I just made in another thread:

As for grounding, just follow a few simple rules:

1) Try to provide one, and only one, ground to each device. This is not always possible.
2) Have a single ground wire on each device all connecting together at a single point, ideally near where power comes in. Tie the AC ground to this same point (unless you are intentionally running part of the system isolated, which can often prove difficult or impossible).
3) Never, never EVER daisy-chain power or ground connections!
4) Where you do use shielded cables (I use them only for sensitive, low-voltage signals like 5V limit/home switches, PROBEs, etc.), connect the shield ONLY at the one end. This will almost always be the BOB end.

My normal practice is to build everything up on a metal plate. It is then OK to tie each ground to that plate, near the device. High current devices, like the DC power supplies and motor drivers should have their grounds, and powers, connected together directly, and keep the wires as short as practical (but no need to go crazy here), to prevent stray currents from affecting other devices.

If you use a metal enclosure (STRONGLY recommended), fasten heavy ground straps (10 ga. stranded wire is good) to any and all movable/removable pieces, like doors, to ensure they are all securely grounded.

Using shielded cables on the motor wiring will help with RF interference (i.e. - you'll more likely be able to listen to the radio while your machine is running). It won't generally do much to make the machine itself more reliable. None of my motor wiring is shielded, and I have no problems whatsoever, other than static-y radio reception in the shop when the machine is on.

That's pretty much all there is to it.

Regards,
Ray L.

[Mad Welder]

Thanks a million Rayoutstanding advice and help.

[edimar]

Almost finished my new Y axis modifications, I must admit the Roton Ballscrew is a much nicer material to turn down(machine), while I still used the Solid Carbide inserts it's a 'softer' Ballscrew than the ones I originally got from Keling as the darn Carbide inserts just kept bouncing off the Keling screw threads.....didn't see and remnants off the rolling dyes on the keling screws but on the Roton screw I had to clean the threads you can see that in one of the pics below....

Hi Mad,

I enjoyed your modification of the Y axis
Would you put more pictures of the back of the router?
How long is this increase?
This modification did not bring vibration to the machine?

Best regards

[Mad Welder]

Hi all again.......back for more advice please,

I wonder could someone explain for me what it means to have an Optoisolated circuit and why would you need one, I have that facility in my C32 bob from CNC4PC, and where do the grounds for the Optoisolated circuit get connected?

and as I can control my VFD through the bob also by the 0-10VDC analogue output on the C32 could you also explain when a 5V supply is required for the the C32 how then can the bob output upto 10VDC?

sorry if these sound like silly questions but I've been scratching my head here!!

[Mad Welder]

Hi Mad,


I enjoyed your modification of the Y axis
Would you put more pictures of the back of the router?
How long is this increase?
This modification did not bring vibration to the machine?
Best regards

Hi there edimar thanks for the kind words, not sure what other pics of the back of the mill you were looking for as they are all included in the previous posts so I included a pic before the final Y axis mount was fitted below and just had a look back through this build and gee I didn’t realise we’d all clocked up 20 pages already but maybe this is what you were looking for in these 6 previous postshttp://www.cnczone.com/forums/1095510-post208.html http://www.cnczone.com/forums/1096008-post217.html http://www.cnczone.com/forums/1073787-post104.html http://www.cnczone.com/forums/1074289-post108.html http://www.cnczone.com/forums/1075393-post112.html http://www.cnczone.com/forums/1076628-post123.html, and the increased Y travel is set to 100mm (4") and you can see the Y axis limits from before and after in the homing and limits page in Mach in photos...2222 & ...2223, I can get more but I've set up my soft limits to stop the table travel while the centre of the table is still resting on the base, or when the X axis Ballscrew is still directly over the front face of the machine base….
and finally no I have no vibration in the Y axis before or after the extension either...

[FannBlade]

Hi all again.......back for more advice please,

I wonder could someone explain for me what it means to have an Optoisolated circuit and why would you need one, I have that facility in my C32 bob from CNC4PC, and where do the grounds for the Optoisolated circuit get connected?

and as I can control my VFD through the bob also by the 0-10VDC analogue output on the C32 could you also explain when a 5V supply is required for the the C32 how then can the bob output upto 10VDC?

sorry if these sound like silly questions but I've been scratching my head here!!

The opti circuit keeps BOB disconnected from the PC. One 5v powers the the "light" that triggers the board to turn on via other 5v power input. Something like that if that makes sense.
The analog output power requires 12v input.

[edimar]

Hi there edimar thanks for the kind words, not sure what other pics of the back of the mill you were looking for as they are all included in the previous posts so I included a pic before the final Y axis mount was fitted below and just had a look back through this build and gee I didn’t realise we’d all clocked up 20 pages already but maybe this is what you were looking for in these 6 previous postshttp://www.cnczone.com/forums/1095510-post208.html http://www.cnczone.com/forums/1096008-post217.html http://www.cnczone.com/forums/1073787-post104.html http://www.cnczone.com/forums/1074289-post108.html http://www.cnczone.com/forums/1075393-post112.html http://www.cnczone.com/forums/1076628-post123.html, and the increased Y travel is set to 100mm (4") and you can see the Y axis limits from before and after in the homing and limits page in Mach in photos...2222 & ...2223, I can get more but I've set up my soft limits to stop the table travel while the centre of the table is still resting on the base, or when the X axis Ballscrew is still directly over the front face of the machine base….
and finally no I have no vibration in the Y axis before or after the extension either...

Hi Mad!

Wow!
You got 100mm travel on the Y axis!!
Now I liked even more of their modification..
Mad Thanks for the tips.
Very inventive work