are drives that sensative??

[.xXACEXx.]

i was wondering ,i have read alot of post where people have have built there drives like the hobbycnc board,and where others have made their own drives with their own chips and components,(by the way my hats off to you all must have a really good grasp of electronics) and i have read about people just buying a cnc kit (more of my boat as im not very electronically inclined, im more ..mechanically inclined ) ,so any way on to the question...

i have seen alot of success and some failure (much more success..but still ..some failure)...and in most cases it seems like it was usually a "user error" but my question was are these drives really that hard to connect to a pc or a b.o.b ?...i dont know much about these drives.in fact i have an old pen plotter my boss gave me to "mess around with" he was gonna throw it away...any way i have not even messed with it as far as taking it apart to get motors out of it or any thing... i say that to say...i am afraid to "break" some old junk printers .so how on earth can i "make my own cnc driver board" i guess my main question is are these drives that easy to burn up ?? are their safe guards to follow to assure that every thing is hooked up right like a check list?
some of these drives are pretty expensive for a hobby so if i do every thing right and blow it up,...its still my fault..
this is more dirrected to those of you that have built your own driver boards that have had little experience with electronics or more of a "generaly speaking" on things to watch for when building a board or connecting one....blowing up a gecko,xylotex,hobbycnc,kelling,ect ect ... board is one of my biggest fears about building a cnc router...spend 350 bux on a driver and then poof its all gone...sounds pretty scary to me!! any thoughts ?? am i just worring over nuttin?? are these thing pretty bullet proof ? and usually a fault of the guy who boght the driver or flipping the switch ..that didnt follow directions??
sorry bout the long post.didnt know a better way to ask all that stuff,and i am not trying to flame any one up that makes these boards ...dont want to start a "my driver is better than every one elses driver" thing here.. just wondering about why some people have to "let the smoke out " of their drives?? thanks guys

[BobF]

If you buy the hobbyCNC package you get motors, drives, most of the power supply, just about everything you need. The driver board is a kit and you have to assembly. It is sensitive to some things, but the instructions are very good with cautions in the right places, and a test at the end to help prevent problems. Its not foolproof, but very good.
This is the one I have experience with.

[neilw20]

Always Read TheFriendly Manual.
Do this thoroughly and make notes unitil you understand the intention.
When in doubt ask.
Never ASSuME. It makes an ass out of you and me.
This will save lots of $'s and give more pleasing results.
Point to point wiring can muck up things.
Lots of different currents can flow to a common point, and trying to send them all through one piece of wire named common or some other name can create weird effects.
A piece of wire is A RESISTOR albeit not very many ohms or part thereof.
A length of wire 0f 0.3 ohms carrying a ripple current of 10 amps (typical value) to a filter capacitor will produce 3 volts of ripple alongg the length of the wire. This is much higher than the TTL switching threshold on a parallel port, or pulse inputs to a stepper driver.
A very good way to create a high powered oscillator don't you think?

It's easy to get the smoke out. Hard to put it back in.
RTFM ! and ask.

[ger21]

Originally Posted by .xXACEXx. but my question was are these drives really that hard to connect to a pc or a b.o.b ?...

Imo, no, not really. Typically, you plug your breakout board into your PC, and from that breakout board, each axis gets two wires. 1) step 2) direction

The drive gets two wires from your power supply, and 4 wires to your motor. For the most part, that's all there is to it.

The problem is that yes, these drives are very sensitive to mis-wiring. Wire your motors wrong, or unplug one while it has power applied to it, and you can usually kiss your drive goodbye.

Go to any stepper drive manufacturers website and download the instruction manual. Read it. Do you think you can wire it correctly? If not, learn how. I'd download a bunch of different ones and see if you can figure out how to connect all of them. It should give you a better understanding of what your up against.

If you're still worried after that, spend the extra money and buy Gecko G203V's. They're about the only ones that you can't kill.

[epineh]

I guess there is no set of rules that will cover all drives, but the advice given so far is spot on, read the manual, every drive has precautions that you should follow, so being aware of them will certainly help.

I have had two episodes of smoke getting out, one was while I was fault finding missed steps on my router, I suspected drivers and motors so I was changing the step/dir signals, on the last connection I had to try to prove what was causing the problem the step wire slipped out of my fingers and I happened to have forgot to turn off the stepper power supply only that one time so guess where the wire fell on, yup the +30V motor supply terminal, result was fried DeskCNC board

Other time was when I built a servo drive that accepted PWM and NOT PWM as a logic input, initial testing proved good so I powered up the drive, and gave it a signal via software, only problem I didn't configure the software correctly and it gave the drive a PWM and DIR signal that shorted both bridges together, blew the servo drive, FPGA card and PC...looking back now I should have used opto's and some logic and the drive would probably still be alive and working.

Accidents happen mine could have been avoided looking back but I have learned a lot by my mistakes and now I make sure I am not tired when connecting something new/untested and double/triple check everything.

The problem with stuff you make yourself is that it will do what you design it to do, if you design it to blow up, it will happily do so, the boards that are professionally made generally aren't made to blow up but they will if not treated nicely, I guess the best advice I could give is that if you don't understand something to ask, someone here will help you no matter how silly you think the question is.

Oh yeah and nothing beats the feeling of when it actually works... I have had SOME successful foray's into the CNC electronic world

Russell.

[jdell42]

Very good advice from Neil and Gerry. I built the hobbyCNC and I had to RTFM 6 times. I consider myself knowledgeable enough to be dangerous... and I was crossing my fingers when I hit the power for the first time.

I am building a Gecko 203V setup now. Easier in some ways as you don't need to build a kit, but harder in other ways as there is no "blue print".

Take your time. Ask questions and double check everything.

[neilw20]

Russell.
BLDC thoughts?
Neil

[Mike Nash]

Just find a friend who is good at electronics to help. That can be easier than learning it yourself. And there's lots of people who get a kick out of helping someone with a project like this if you don't lean on them too heavily.

I suggest starting a thread looking for local help for your project. Burning things up can get pricey.

[epineh]

Hey Neil, I wimped out and bought a VFD and 0.55 KW 2 pole motor, but I still want to pursue the BLDC drive, I just got your email, (wife has about 200 emails a day, it is hard to sift through).

I will pick it up in about a month's time, thanks for your email and your time.

Russell.

[.xXACEXx.]

so is it safe to assume then if you blow a board,99% of the time it is your own fault then...like plugging in a "step" wire where a "dir" wire shoulda went..i would like to get "build your own" board because of the price,but returning it 3-4 times before it even moves a axis is not my idea of fun...but then again.if you buy a "pre-built" board and put a wire in the wrong place while wiring it to you pc or the b.o.b. then youve just burned it again...i like the postabout downloading the manuals to get an idea if your doing it right...if it says to plug step wire here and you plug it somewhere else...DOH! what else did you expect it to do but maybe burn....lol drive manufactures think of all this in advance then? and tell you where to put this wire ,and where to put that wire..?..if so ..easy ..then how (othere then dropping a wire on a live board... hate to hear that by the way) how.. can you mess up on a pre-built board ,with good instructions.for wiring it up..especially on a kit designed to work together..like driver(s) ,and powersupply,motors for said driver(s) ?? i guess i have a over active worry gene..lol or murphy's law gene..is it really just..read the instructions,place wire herethere,and so on...turn on power (or check voltage where told to do so)..and plug and play..if so..this is a great thing you drive manufacturers have done !! thanks for your efforts you have let the "magic smoke" out for us before we did it our selves

[neilw20]

Just be confidant, and use due care.
Are you careful spending money?
Try to understand each part of what you are doing.
Don't TRY things. Be a little more analytical. Analyze and PLAN.
The information IS AVAILABLE. Excess PATIENCE is not optional.
I notice you do not use the shift key. You must dot the T's and cross the I's.
Was that an error I just made?

[ger21]

Originally Posted by .xXACEXx. so is it safe to assume then if you blow a board,99% of the time it is your own fault then...like plugging in a "step" wire where a "dir" wire shoulda went..

Mixing up step and direction signals won't hurt anything. Unless you put them where the motor should be connected.

Generally it's the motor wires and power supply wires you have to worry about.