Ready Steady Eddy

[EddyCurrent]

Wow eddy, that's a great looking control panel!

Thanks

Do you mean rather than going INVERTER -> Through the conduit -> DIN mounted terminal -> panel mounted connector, you will be skipping the conduit/DIN terminal and wire straight to the panel connector? Is this to reduce the chance of noise/interference?

Yes and Yes

Do you have any wiring diagrams you would care to share? I can identify some of the components in your pic and guess how some connect but a bit more detail would be great.

Where are you planning to mount the various connectors? I guess the bottom panel?

No connectors, I'll be glanding off the cables at the bottom and wiring into the DIN rail mounted terminals

I see you have an EStop on the front but do you have any other provision for machine mounted estops/limit switches/home switches?

See drawing, yes, I'll probably include in the E/stop circuit the following; ultimate travel limits, machine mounted E/stop button, spindle motor over temperature sensor, AM882 alarms.
The homing limits are wired separately they are not in the E/stop circuit.

Are those grey jobbies at the bottom din mounted terminal blocks?

Yes, the earth terminals provide an easy way to tie all the screens down.

Can you recommend a supplier for the various parts (DIN rail, cable conduit etc)?

These may not be the ultimate cheapest but won't be far off, I was surprised how Farnell prices have improved lately for some items, or maybe it's others bumping theirs up ?

Home - Chalon Components - various bits and pieces
Farnell United Kingdom | Electronic Components | Electronic Parts - DIN rail, trunking, other small bits
Quickbit - CY cable
Electronic Components from Rapid - the Electronic Parts Specialist - small power supplies, large capacitor
Transformer Manufacturer UK - Airlink Transformers - toroidal transformer

[cncJim]

Thanks again Eddy, you have saved me many hours/days of Googling!

• What software did you use for your wiring diagrams? Looks very good and easy to follow.
  

• “No connectors, I'll be glanding off the cables at the bottom and wiring into the DIN rail mounted terminals”

  Of course! I have been specing out the various connectors I would be needing to hook everything up (not cheap!) but this way make far more sense! Even more so the fact that I plan to fix my control panel under the machine. Doh!
  
  
• Do you plan to have any control for things like Air/Water/Vacuum in the panel or maybe just have them switchable on the machine? I plan to have them all individually controllable (ON-OFF-ON with spindle).
  
• I like the idea for the spindle motor over temp. Have decided how you will implement this at the spindle?

Also I spotted your link to the “System Design for Control of Electrical Noise” pdf in another post. Just been reading it, great info, particularly the parts dealing with “clean/dirty/very dirty” cable runs. Very interesting.

Maybe not so much use in your case Eddy (?), but in case anyone else finds it useful I found a neat cable entry wiring solution for cabinets - Great for things like the parallel port cable:-
Weidmuller Cabtite

[EddyCurrent]

What software did you use for your wiring diagrams? Looks very good and easy to follow.

Visio but any 2D CAD will do, it's just that I had already created the symbols with it. By the way a good source for electrical symbols is the Telemecanique catalogue, you have to draw them youself and save as a block but it's still a great resource.

Do you plan to have any control for things like Air/Water/Vacuum in the panel or maybe just have them switchable on the machine? I plan to have them all individually controllable (ON-OFF-ON with spindle).

No not particularly but I have included some spare terminals if need be with the idea of adding another breakout board, the Smooth Stepper has connectors for 3 ports. The enclosure is pretty full now and I like everything to fit onto the backplate, other than door mounted buttons etc.

I like the idea for the spindle motor over temp. Have decided how you will implement this at the spindle?

The spindle is an ELTE 2.2kw TMPE3 12/2 and has a built in switch for temperature.

Also I spotted your link to the “System Design for Control of Electrical Noise” pdf in another post. Just been reading it, great info, particularly the parts dealing with “clean/dirty/very dirty” cable runs. Very interesting.

In my panel all the low level signal wires go in the right hand vertical trunking while the stepper motor and power wiring are in the left hand vertical trunking. The stepper motor wiring and spindle motor wiring are in screened CY cable, all screens earthed at the terminal rail and nowhere else.
If anyone is concerned, it might be worth their while to look up IP2X for electrical panels, one way is to put a full perspex sheet over the whole guts secured by screws at the corners.

[JAZZCNC]

Eddy Save your self some inputs and just wire the Home and limits in series. If using separate home switches to limits you'll just need 2 inputs and if sharing same switch just one.!

Not sure if your aware or not but by default when Mach homes it just moves one axis at a time so can be wired in series with no problems. You only need on separate Inputs if you change the homing script so all Axis home together. It's actually better leaving in default mode because it's very easy to damage tools etc because when you press Ref all home then all 3/4 axis set off homing at same time and it's very easy for tool to catch something because the Z axis hasn't lifted enough before X or Y drag it into clamps or material etc.
Mach's default homing first lifts the Z axis then Y axis followed by X axis making it safe. In practice when wired in series this also means tripping any switch can set the axis being homed at that time.? Ie pressing X axis switch while Z axis is homing still sets Z axis home position.? Mach doesn't know or care which switch is pressed, all it cares about is seeing the input state change then setting the coordinates for the axis it was homing at that time then moves onto the next axis etc.

Also spotted you have the ABB 355 vfd same has me. I don't see any reference to the water pump on your schematic and I also don't see any reference to it from the VFD so not sure if your using WC spindle or not.? . . But What I do is use the On board relay on the VFD to turn pump on/off this way it's only on while spindle is spinning.

[EddyCurrent]

Eddy Save your self some inputs and just wire the Home and limits in series. If using separate home switches to limits you'll just need 2 inputs and if sharing same switch just one.!

Thanks, yes, I found out about that while testing the setup here.
http://www.mycncuk.com/forums/market...html#post51374

Also spotted you have the ABB 355 vfd same has me. I don't see any reference to the water pump on your schematic and I also don't see any reference to it from the VFD so not sure if your using WC spindle or not.? . . But What I do is use the On board relay on the VFD to turn pump on/off this way it's only on while spindle is spinning.

Air cooled ELTE spindle, yes good idea to use the relay for that.

[EddyCurrent]

My breakout board has a charge pump output that I'm currently not using. Mach3 is using it but I think I will look at incorporating it into the hardware stop circuit as your drawing shows.
Also, and this is very important but open to interpretation, I am not removing power from the spindle inverter during emergency stop, I mentioned this is another post. The reason is that the inverter can stop the spindle faster than it will stop on it's own, it does this by applying dynamic braking. Other options for bringing the spindle to a timely halt would be a spring loaded mechanical brake or as in the case of my table saw, a DC injection braking system. Removing power to the inverter via a contactor is the obvious emergency stop strategy and it could be said that removing power from the inverter under load will damage it, that might be true but better to have a damaged inverter than a damaged limb. According to the machinery Regs. which won't apply in a private houshold situation, the spindle should stop within 10 seconds, now I've not had my spindle up to speed yet so time will tell how long it takes to stop on it's own.

[cncJim]

Also, and this is very important but open to interpretation, I am not removing power from the spindle inverter during emergency stop, I mentioned this is another post. The reason is that the inverter can stop the spindle faster than it will stop on it's own, it does this by applying dynamic braking. Other options for bringing the spindle to a timely halt would be a spring loaded mechanical brake or as in the case of my table saw, a DC injection braking system. Removing power to the inverter via a contactor is the obvious emergency stop strategy and it could be said that removing power from the inverter under load will damage it, that might be true but better to have a damaged inverter than a damaged limb. According to the machinery Regs. which won't apply in a private houshold situation, the spindle should stop within 10 seconds, now I've not had my spindle up to speed yet so time will tell how long it takes to stop on it's own.

Good info, thanks.
If I had your VFD rather than my cheap Chinese one, I might be more inclined to trust it to stop the spindle during an Estop as well.

Removing power to the inverter via a contactor is the obvious emergency stop strategy and it could be said that removing power from the inverter under load will damage it, that might be true but better to have a damaged inverter than a damaged limb.

Why would the inverter be damaged in this situation? Is it because once the power is cut to the inverter the spindle acts as a generator and this generated current can damage the inverter?

I would like to have a safety system that does not compromise at all on safety but has the best chance on leaving the equipment undamaged (also how do you test an estop circuit if testing it may damage the equipment?!?).

I'm not that keen on the mechanical breaking solution, so that leaves the following:-

EStop

• Dynamic/Rheostatic braking
  Cut cables from inverter to spindle and attach spindle to a bank of breaking resisters to apply dynamic breaking (is this even how it works!?!). At same time cut the run cable to the inverter.
• DC injection braking system
  Same as above but DC injection brake cuts the link from inverter to spindle and applies DC to the spindle to stop it.

I like the idea of the DC injection braking system but they seem pretty expensive (RS DC Injection Brake @ ~£160 with VAT!). I wonder how easy/cheap it would be to do dynamic braking (without the vfd)?

edit - Just noticed my Huanyang vfd has terminals to add a braking resistor. If power is removed from the inverter would this still be used/effective? would it cause damage to the inverter?

[Jonathan]

Removing power to the inverter via a contactor is the obvious emergency stop strategy and it could be said that removing power from the inverter under load will damage it, that might be true but better to have a damaged inverter than a damaged limb.

Unlikely to cause significant damage to your limbs due to spindle's low inertia, so personally I'd rather it damaged the limb as that'll get fixed for free on the NHS, unlike the VFD.

Why would the inverter be damaged in this situation? Is it because once the power is cut to the inverter the spindle acts as a generator and this generated current can damage the inverter?

Vaguely.

Just noticed my Huanyang vfd has terminals to add a braking resistor. If power is removed from the inverter would this still be used/effective? would it cause damage to the inverter?

If you remove the power, the inverter can't do anything as it will only remain switched on for less than 1/10th of a second before the capacitors discharge. So no, it wont apply the brake.

I would like to have a safety system that does not compromise at all on safety but has the best chance on leaving the equipment undamaged

In that case you need to separate 'fault conditions' from safety concerns - e.g hitting a limit switch or stepper driver fault signals do not pose safety hazards, so treat them as such and wire it so the machine just pauses. The only one that warrants fast and complete shutdown is pressing the e-stop, as that's what you can supposedly do if you're about to get hurt.

Now regards the Kill power or Kill signal to VFD then I used to be Kill Signal guy but I'm now I Kill all power. Reason being what happens if the signal breaks or Even the VFD goes faulty.?

The signal should be wired such that if the wire's broken or otherwise interfered with the signal changes state and the system stops. The VFD going faulty sounds exceptionally unlikely, but if you're worried about that then just have a timed relay to switch the VFD power off a couple of seconds after the signal (as mentioned earlier), since by that point the spindle will have stopped so you wont damage the VFD by cutting the power, and if it's not stopped then the VFD has gone faulty so you probably don't care about risking damage to it by cutting the power.

E-stop is hit due to Limit or some other none spindle related condition then doesn't really matter how long spindle takes to slow down and coasting to a stop isn't long or problem.

My new spindle takes 107 seconds to stop from full speed if left to coast. I tend to agree that it's not really a problem though.

*emergency stop button pressed - strategy 1 or 2

Two, see above. You could take advantage of the enable signal on the stepper drivers to disable them, then link cutting the power to the delay associated with the VFD.

I also think the braking resistor is not required because of the fairly low inertia of the load.

Yes - the internal resistor is sufficient to stop the 2.2kW spindles in less than a second, so you can easily implement the above method.

(3000th post... )

[JAZZCNC]

The VFD going faulty sounds exceptionally unlikely

Not that unlikely really has I've got one here that did just that in that it wouldn't turn off thru a signal or the control panel. Turned out to be faulty panel and was replaced by ABB but the fact was it stayed bloody on so no signal would have turned it off.!!

[Jonathan]

Not that unlikely really has I've got one here that did just that in that it wouldn't turn off thru a signal or the control panel. Turned out to be faulty panel and was replaced by ABB but the fact was it stayed bloody on so no signal would have turned it off.!!

What's your point? The timed switch off mentioned twice (now three times) in this thread would have turned it off. Also you can't judge how likely something is with such a small sample size.

A couple of months ago I got a 15kW ABB VFD. Wired it up correctly and 5 minutes later the input rectifier blew up leaving my ears ringing for about half an hour!