ELECTRONICS WIRING

[A_Camera]

I will add another thought here. Switched Mode power supplies are very fine for many things, but you should NOT use them for motor drivers. The RFI from the power supply can interfere with the switching in the driver. Instead you should use a very basic power supply: transformer, diode bridge, and capacitor. No, not even a regulator chip. By and large, motor drivers are built for this sort of voltage input. And if it sags a bit at the rare peak load - too bad, don't worry about it.

Cheers
Roger

Exactly. But unfortunately many kits include a power supply and that power supply is always a switching supply. The sellers of those kits don't have a lot of knowledge about the products they are selling and many of the buyer also lack the knowledge in this regard, so they buy what seems to be a very good alternative. Switched supplies are smaller and lighter and everything is boxed, so they are really plug and play. Analog supplies are larger and heavier and even if it is simple to build, not everyone can do it, and buying ready made ones are more expensive than switching supplies, even though they are very simple to make, so many people, even with electrical knowledge, ignores them, at least initially, because it is simpler to get started with a switching supply.

To complement your comment, yes, analog supplies are in theory only contains a transformer, a diode bridge and a large capacitor, but it needs a little more, like it is a good idea to have a fuse on every leg of the output and a slow starter at the mains AC input to the transformer to avoid the current rush during start-up.

[CitizenOfDreams]

I will add another thought here. Switched Mode power supplies are very fine for many things, but you should NOT use them for motor drivers. The RFI from the power supply can interfere with the switching in the driver.

I disagree. Switching power supplies are successfully used to power devices much more sensitive to RFI than a motor driver - such as audio amplifiers, computers, low noise radio frequency converters and much more. If we are talking about high power applications, then there are devices such as RF transmitters used in satellite communications and TV broadcast - hundreds of watts of output power and input signals in the microwatt range.

[RCaffin]

Hi A-Camera
All true, I agree. But no-one said this CNC stuff was simple ...

I have a magnetic cutout on the mains input to the spindle driver power supply and magnetic cutouts on the supply into each axis motor driver. But that means a more complex eStop circuit to handle the possibility of one motor driver popping the breaker (because the table ran into an end stop is the usual reason). It also means I have to sense the status of the spindle power supply so that I don't run a stationary cutter into a solid block of metal. M3/M4 always checks the spindle supply status before starting.

Hi Citizen
Ah well, check with your motor driver supplier. I found that many of them expressly disliked SMPS units.

Cheers
Roger

[A_Camera]

I disagree. Switching power supplies are successfully used to power devices much more sensitive to RFI than a motor driver - such as audio amplifiers, computers, low noise radio frequency converters and much more. If we are talking about high power applications, then there are devices such as RF transmitters used in satellite communications and TV broadcast - hundreds of watts of output power and input signals in the microwatt range.

Yes, but high quality devices cost a bit more than those included in kits or sold cheap on eBay. I am not sure that audio amplifiers are that critical or difficult applications as precision positioning devices, but sure, switching supplies are used probably even within robotics and auto manufacturing business, as well as many others where accurate positioning and very high reliability is required, but then we are talking about a different price range all together, including the power supply...

Also, as well as I know, real audio nerds prefer analog power supplies also. In computers it doesn't matter, you could fairly easy filter, so no big deal, nothing happens if a few extra pulses are generated by the power supply, the output of the supply will not change. Computer business is also costs and weight driven. It would be difficult to sell computers with analog supplies because the weight and the costs would significantly increase. Weight is NOT a disadvantage in a CNC, quite the opposite, if the PSU is part of your machine, it is better if it is heavier, but if my computer would suddenly become 15kg heavier I would not like that.

[Sesh]

OK,
Wow, so much learning, Let me try and catch up.

1. Rule 1: Ground has to run all the way to ground.
2. Rule 2: When there is an electrical component powered by a power source, the voltage is GIVEN to the component whether it wants or no, and current is TAKEN by the component as required. So every electrical component's power need to be understood as voltage being the maximum limit, and the current as the minimum requirement.

I now understand the logic behind the choice of power supplies that you have made, John. Thank you very much.
Following rule 2, I can also consider the Meanwell SE-450-36. This guy outputs 36V at 12.5A, if the price is not very much more, I might as well go for that.

The PS for the board, I have attached a closer picture of the relays. this looks like I need a 12V, 12A powersupply?


Now coming to the actual power supply. Multiple opinions here.
Simply put, my choice seems to be to buy a power supply, or to make one.

Roger, I do not have enough skills to build the Power supply you are recommending at this particular time. It's very tempting to try, though, simply because it is something I have never done before. That, however, would mean that either you or someone else with immense patience will have to hold my hand while I'm doing it. My wiser half tells me I should attempt this after I have my machine up and running, as part of an upgrade program :-) But please share some links if you can.

Option two is to buy one.
Here I have a supplier locally for this Chinese brand, hence my looking at that, it's easy to lay my hands on.

Regarding the brand
One thing I do know, is that there are Chinese products, and there are Chinese products. Although famed for being non reliable, you do find some brands that last really long, and don't conk off in a month after buying. I do not know if this company Meanwell falls into that category. I have used cheap Chinese timers in my garden, cost me Rs.600 (about 9 Dollars), it's been operating continuously for the last 4 years, and going strong. One never knows until one tries. I first encountered this brand when I received one as part of the Shapeoko2 kit, and I assumed the brand must have passed some sort of quality threshold to have been included in the kit.

Yes, but high quality devices cost a bit more than those included in kits or sold cheap on eBay. I am not sure that audio amplifiers are that critical or difficult applications as precision positioning devices, but sure, switching supplies are used probably even within robotics and auto manufacturing business, as well as many others where accurate positioning and very high reliability is required, but then we are talking about a different price range all together, including the power supply...

A_Camera, can you give me an example of what kind of power supplies you are suggesting? What is the price range?
Also would like to know in what way the Chinese powersupply actually impact the ouptut of my machine. Will pieces get cut less accurately? Or will it reduce the life of the drivers?

Roger, can you clarify this:

The RFI from the power supply can interfere with the switching in the driver.

The point of all this is for me to make components for kinetic sculptures, so if the power supply is going to affect that, I'll have to do a rethink.

Thanks and Regards,
Seshadri

[A_Camera]

A_Camera, can you give me an example of what kind of power supplies you are suggesting? What is the price range?
Also would like to know in what way the Chinese powersupply actually impact the ouptut of my machine. Will pieces get cut less accurately? Or will it reduce the life of the drivers?

I don't suggest any power supply. I made my own, but it seems you don't have enough knowledge to do that and I don't have the time to assist you from scratch to build one. Sorry, but I think you better off buying a ready made one. Anyway, if you buy a switched supply buy one which gives you between 40V and 50V and NOT less than 12A, but an absolute minimum is the 36V 12A you considered. Definitely not less than that.

[john-100]

Hi Seshadri

I have looked up the 12V relays part number and they have a 400 ohm coils that will take 30mA from the 12V supply

if the 12V supply is just to power the breakout board a 12V 500mA supply will be more than enough to power the board

I estimate at most its going to be about 160mA
( 16mA x 6 if all 6 stepper driver inputs are high and 60mA for both relay coils + 2 or 3 mA for the rest of the board )

John

[RCaffin]

What John wrote about the 12 V relays. The current rating shown on top is what they can switch, not what they need. The current needed to drive them is small.

The RFI from the power supply can interfere with the switching in the driver.
The motor drivers often need a fairly quiet power supply. The RFI noise on a switched mode PS can, sometimes, affect their operation. I guess the thing to do is to try a bought power supply first and see if it works OK.
Question: do you have a multimeter? If not, that is something you will have to buy anyhow.

The learning curve on this srtuff can be steep!

Cheers
Roger

[Sesh]

Hi, everyone,

Firstly, apologies for disappearing for a while. A couple of projects came up, which meant putting everything fun on hold.

Secondly, A big thanks to this forum, and especially John, Rojer, and A_Camera for helping out.

In november, I had small pockets of time free, not enough to dive into my workshop fully, but enough to frustrating, so I decided that I would play fiddle with some electronics, as my hands were itching to try something out, after all those questions I had asked.
So I got hold of an arduino, and in 15-20 days, managed to hook up an rtc module to it and an LCD, to run a few relays(AC240) for misting my orchids. A whole world of possibilities opened up. I even managed to learn soldering enough to make this circuit board, and tested it out using a a normal light bulb. I am figuring out a safety feature, post which it will get installed in my garden.

It's pretty basic stuff for you guys, but for me who at the beginning of the thread, didn't know the difference between voltage and current, It's been supremely empowering.
Again, thank you very much for your patience and generosity.

Fast forward to 2017,
Last week, I got the power-supplies as discussed earlier, and wired them up. The moment I switched on the power, something started burning, and two of the drives started smoking. One of them quite heavily. I switched everything off,
and checked all my wiring. There was nothing wrong with the wiring anywhere, but one of the drives had definitely gone to heaven.. I had written to the vendor I bought these from, and the wiring was right as per their instructions too.

I am definitely inclined to point the finger at the product, and am considering changing the electronics entirely, unless I am able to figure out what I did wrong. These drives were very cheap (3 of them cost me approx 70$) , which is why I risked them on my learning curve:-). I have wrote to the vendor again, and am waiting to hear from them.

If this doesn't work out, I will need help with new electronics for my machine. Do I then start a new thread, or continue with this?

Regards,
Seshadri

[steve323]

Hi Seshadri,

Sorry about your first attempt mishap. That thing of thing often happens to me. I have a great plan in my head, but it often takes a few tries to get it right.

One option for the electronics is to buy a complete kit with motors, cables, G540 controller, and a power supply. Search EBay for "G540 motor kit" and a few will pop up. Prices appear to be in the $600-700 range which is a small premium over the individual parts cost. G540 = $300, power supply = $100, 381 oz stepper motors = $40 times 4 motors, cables = $50.

Steve

[Sesh]

Thank you Steve.
This has opened a whole new can of worms for me :-)

I now need to figure out something that gives me maximum flexibility for growth/scaling later, primarily because I have no clue as to what I am going to eventually need.

There are two machines in the pipeline. I am buying a cncrouterparts machine, which I am going to be using primarily for machining brass, aluminum, and wood. I will use it to refurbish the shapeoko2 I already have, to use a drag knife or a low power laser head for cutting paper, card, leather or cloth. The Shapeoko2 definitely needs an electonics overhaul. The purpose of these machines is to make moving parts for some kinetic sculptures I have in mind. That essentially translates to: I'm ok with even a month of DIY, building, learning, alignment, setup, etc. But once setup, I need to be able to focus on the creative, not constantly tinkering with the machine.

I have been leching at the Geckodrives for some time now:-) I think the time has come to take the plunge, and buy the G540. So one end plugs into the parallel port, and the other end to my motors.

For software, I am leaning toward linux cnc, even though I have never used linux before. I believe the G540 works with linuxcnc.

How stable is linuxcnc? Does one generate the toolpath inside linuxcnc? or is it just for cutting?
What software can do both toolpath generation and machine control in one place?
Can Mach4 do that? Is mach4 stable?
Is it possible to run both machines from the same pc?(like how one chooses differrent printers from the laptop)

What about scalability? For example, Is it possible to add encoders to this pipeline later?

Too many questions as of now, but I guess one has to start somewhere..

Regards,
Seshadri

[ger21]

What software can do both toolpath generation and machine control in one place?

Any control software that can create toolpaths or g-code will be far more limited than an actual CAM program.

[Sesh]

But are there any available for a "not yet proffessional"?
I was googling through the list of software on this forum, and in some cases, i couldn't figure out. For example, there was something called esprit that looked like it did, but it looked expensive. Also I coudn't find the price anywhere.
I already have access to CAD sofware, as i am a designer, so rather than a cad-cam grouping, a cam-control grouping would be more useful for me.

[Sesh]

Anyways,
Bought the G540, Steve, should be reaching me on saturday
I'll be continuing the discussion on the gecko forum
Regards,
Seshadri

[jcoldon]

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eithernet conection is a way better setup

[Sesh]

CHECK THIS SITE THEY HAVE EVERY THING YOU NEED Breakout Boards Archives - Stepper Motor | Stepper Motor Driver | CNC Router | Laser Machine | 3D Printers For Sale Stepper Motor | Stepper Motor Driver | CNC Router | Laser Machine | 3D Printers For Sale GO EITHER SMOOTH CONTROLLER usb is slow and only as good as your computer mother board
eithernet conection is a way better setup

As of now i was thinking of using the paralell port. Is the ethernet connection better?