[Aemornion]

Hello all,

Quick question, which hopefully will be answered in a flash by someone smarter than me. =)

In the process of generating my parts list, and I am looking into the motors drivers and controllers.
Planning on building a 3x3' square or slightly smaller router, using acme 1/2-10 2 start and 8020 Aluminium.


I don't have a parallel port, so I will be using a smoothstepper, but I am a bit confused on its role.
Is the smoothstepper essentially a usb ->parallel adapter. Which I would then plug into the below ebay kit?

Say for instance I decided to use this kit from ebay (china)
ebay item number 280612051870

or does the smooth stepper already perform the function of half the above board, and all I need to find is the actual stepper controllers themselves?



But, more to meat of this post.
Basically, I wish to pick everyones brains of whether or not, buying an ebay stepper kit (such as the above) is a decision I will come to hate myself for or not down the road?

Thank you for any comments anyone has to offer

[aarggh]

Nooooooooooo!

Run from that auction, the steppers are completely useless at 18mH inductance, I've never seen any so high. They would need a 135VDC power supply, according to the industry standard calc of 32 x the square root of the inductance = power required.

And the controller, even worse garbage. Search tb6560 and problem in these forums, you'll find thousands of posts from people who thought they were worth getting cause they were cheap, only to find they are plagued by bad design, and numerous problems.

Ideally you want steppers as low inductance as possible, 287-380oz-in are widely available with around 2.3-3mH inductance at most. These will match beautifully with a decent controller such as a G540 or similar, and a decent 48VDC power supply.

Buying stuff like the cheap Chinese controllers, and abysmally bad steppers like is literally throwing money away, as you'll never get it working properly. Especially with the ludicrously low power supply of 24VDC that comes with that kit!

cheers, Ian

[James Newton]

As aarggh says: "AARRGGGH!" Don't buy that crap. If you can't afford a G540, and you know your way around a soldering iron, then take a look at my THB6064AH driver kit.

[amina]

i have problem with my tb6560 board. I wired 3 stepper motors, X and Z axis work fine, but the Y axis motor starts to run as soon as I plug the board to power. its running uncontrolled, and twitching a bit, so i can't jog it in Mach3
Does anyone have idea whats wrong ( I triple checked all the wires, and setup in Mach3)

[aarggh]

i have problem with my tb6560 board. I wired 3 stepper motors, X and Z axis work fine, but the Y axis motor starts to run as soon as I plug the board to power. its running uncontrolled, and twitching a bit, so i can't jog it in Mach3
Does anyone have idea whats wrong ( I triple checked all the wires, and setup in Mach3)

It's a TB6560 board, they're designed to not work.

cheers, Ian

[Aemornion]

My apologies for the delay.

Thank you for answering my question. I will stay away from the eBay China boards. =)
I wish I could justify spending the money on the gecko. =/ Perhaps in the future version I'll feel the need to upgrade.

That kit seems interesting and right up my capability and price range!
How would that kit interface with the smoothstepper?
Just from the smooth stepper output? Or is an additional board needed in between?
As mentioned in the first post. I'm a little foggy on how the smoothstepper would work.

Thank you

[James Newton]

The Smoothstepper is a motion controller, not really a USB to parallel converter. They are close to the same thing, but not really. Let's see if I can explain the difference.

The USB to parallel converter is designed to send out 8 data bits in parallel (on 8 wires) with a pulse (strobe) on another wire each time the data is ready. That is SPP (Standard Parallel Port) signaling. A "real" parallel port in a PC can change the data bits around any way you like, so you can put out a direction signal on 4 of the 8 and pulse the other 4 each time you want a step from each of 4 motors. USB to parallel port converters don't really allow you that sort of control over the data pins.... they control the timing, which is bad for running stepper motors because you need a nice acceleration (slow steps at first, and then faster and faster, etc...) to keep the motors from stalling under the mass of the axis on your CNC machine.

A motion controller, on the other hand, also has 8 (or more) wires, 4 direction and 4 step, but it controls the speed and timing of the step pulses to make that nice acceleration curve. And so on.

In either case, in ANY case, the output is 1 step, and 1 direction, per axis. ALL stepper motor drivers take step and direction inputs. Anything that connects those signals will work. You could literally just solder wires between the pads on the smooth stepper and the pads on the stepper controller... But that wouldn't be nice, or easy.

As far as I can tell (they aren't very clear in their documentation) the Smoothstepper comes with ribbon cables that plug into the connector on their board and have a standard parallel port DB25F on the other end. At the very least, you can get cables for it that do have that:
CNC4PC

This makes sense because, historically, people used standard parallel port connectors on the back of the PC (DB25F) and hooked that up to a BOB (Break Out Board) which then connected to the stepper drivers. We have a BOB for our drivers with a cable option that connects to the standard DB25F and then a ribbon cable that connects the BOB to the drivers.

The Smoothstepper docs say they will connect to any standard parallel port based BOB, so I can't imagine why that wouldn't work.

[SignsOfHa]

James Newton: thank you for a clear explanation! Thank you all for sharing your time & knowledge. I was on the path to buy Chinese..... Now I know how much more I don't know.