TB6560 worth

[bobgrant]

I know there are disappointments with the TB6560 stepper boards and issues with the authenticity of the same driver chips offered for sale on eBay.

But that said, would anyone be interested in genuine TB6560s chips on a properly designed PCB with "REAL" opto isolation, over voltage protection and conservatively rated at 2A@35V.

I'd like to hear your thoughts.

[James Newton]

The problem with any SMT, monolithic driver like the TB6560 is the extreme cost of repair. Things go wrong in the real world... motor leads come loose, or wires get connected wrong, or power supplies spike, etc... and when something does go wrong, doing what amounts to surface mount repair to replace an expensive chip that encompasses every function of the driver is just not reasonable. Although some people do it.

And on top of that, the TB6560 itself is fragile. It does not incorporate protections offered in many other driver chips (e.g. the SLA 7076 or A3977 are much more rugged) so frying it is very possible.

All in all, I personally recommend drivers that use separate power drive transistors. They can be easily replaced at very (very) low cost and so make your investment in the driver as a whole more secure. If something goes wrong (hint: It will!) then you can replace the drive transistors easily for a few dollars with an easy, through hole repair that anyone can pull off with the cheapest soldering iron.

And.... honestly? Competing with the insane claims and prices of these scam artists from China is going to be very, very, very difficult. People just don't seem to have a sense of "too good to be true" anymore.

And finally... a good design for the 6560 has already been done:
Toshiba 6560AHQ

There are other places in the market that might be better to look into: Why isn't there a low cost kit or open source design for a general purpose, parallel port opto-isolator? Some people worry about isolation, others don't (I think using an old PC and Turbo CNC without isolation is the smart move... I don't want my nice iron anywhere near a mill) so putting isolation on every driver is an unnecessary expense. It should be available as an option to add to /any/ controller by plugging it in between the PC parallel port and the driver. But I can't find anything on the market that does it...

Other ideas: Design a CNC mill that can be built from large, heavy, very low cost materials which are commonly available from junk yards or hardware stores which uses a small, light, easy to ship part to join those base structural pieces and provides precise alignment. Design an open source, high power, discrete bi-polar driver. Design an effective encoder/control system that accepts step and direction signals and allows the use of DC motors with a drive system (gear box or belt drive or ...) to replace stepper motors. And so on... lots of good ideas out there.

[bobgrant]

I share your sentiment, the TB6560 might survive in a modellers light duty foam cutter but otherwise become an exercise in fustration on the 'big irons'.

Re: Opto Isolation
I'm all for isolation, in fact, were it practical, I'd use a battery powered laptop or one with a two pronged power supply to be certain.

Thanks for those ideas - definately food for future thought.

[James Newton]

I need to retract what I said about a good design already being done. NONE of the designs that I've seen for a driver based on this chip address the FACT that the datasheet specifically and adamantly calls for the logic power to be stable BEFORE the motor power is applied! It's amazing to me that any of these drivers work at all... This certainly explains why so many people have reported random frying of the chip... if it happens to come up the wrong way in the logic area, the motor power will fry the chip. It's a crap shoot. For more detailed discussion of this problem see:
http://www.cnczone.com/forums/steppe...60_driver.html

[crob09]

I need to retract what I said about a good design already being done. NONE of the designs that I've seen for a driver based on this chip address the FACT that the datasheet specifically and adamantly calls for the logic power to be stable BEFORE the motor power is applied! It's amazing to me that any of these drivers work at all... This certainly explains why so many people have reported random frying of the chip... if it happens to come up the wrong way in the logic area, the motor power will fry the chip. It's a crap shoot. For more detailed discussion of this problem see:
http://www.cnczone.com/forums/steppe...60_driver.html

I think it depends on where the Logic is being supplied from, if it's from one of the pins on a DB25 the supply logic is very stable at 5V, a person just has to remember to turn on the PC before powering up the main supply.
I have also used an external logic and did experience some troubles, but for other reasons.
The drivers aren't too bad and are reliable if the circuit they are in is a good one, an example of a bad or questionable circuit would be this tb6560 driver board on a Rep-Rap machine , a good circuit would be this Red TB6560 driver board
Both are DB25 style boards and both obtain logic power from one of the BD25 pins. I have seen people use Arduino PLC's to run machines, although they are not using TB6560 IC's.

[bobgrant]

Trying to compete with $45 for a 3 axis Chinese controller, even one that you know to be riddled with design flaws is very difficult, especially when so many hopeful users are attracted by the price.

Over the past year I made a few attempts at a proper TB6560 implementation that would have been pre-assembled for folks to use, but I've found that the parts and layout needed to protect the device from failure simply add to much to the final kit price. In short, the pin-out for the device is so badly thought out that the layouts I've seen or have created are less then ideal.

That said I'd like to gauge the level of interest in a 50V 5A drive. I think it's possible, what features would you like?, what don't you like?, and since we all got to eat, what do you think it's worth?.

[crob09]

Trying to compete with $45 for a 3 axis Chinese controller, even one that you know to be riddled with design flaws is very difficult, especially when so many hopeful users are attracted by the price.

Over the past year I made a few attempts at a proper TB6560 implementation that would have been pre-assembled for folks to use, but I've found that the parts and layout needed to protect the device from failure simply add to much to the final kit price. In short, the pin-out for the device is so badly thought out that the layouts I've seen or have created are less then ideal.

That said I'd like to gauge the level of interest in a 50V 5A drive. I think it's possible, what features would you like?, what don't you like?, and since we all got to eat, what do you think it's worth?.

I am no authority on the topic but 50V 5A for a TB6560 is nuts http://www.toshiba.com/taec/componen.../382/27885.pdf
That's the datasheet.
You will need a different IC if you want to run that Voltage rating with that amperage, remember you're talking 250W, that's crazy power, besides what stepper will you use that potentially uses 5A and needs 50V to run?
If you manage to make something work, I wouldn't pay anything for that the standard Nema 17 motor rated at 2.5A 12V does just fine.
Try the MK4 or MK4c from SOC, or you can try a micro controller with some driver boards.
BTW, all you need are a few diodes to protect the circuit.

[bobgrant]

I didn't mean a 50V supply for the TB6560 but for a new design, beside, it's difficult enough keeping the TB6560 alive at 24V.

>> besides what stepper will you use that potentially uses 5A and needs 50V to run?
I think you are confusing driver ratings with motor specifications.

[crob09]

I didn't mean a 50V supply for the TB6560 but for a new design, beside, it's hard enough keeping the TB6560 alive at 24V.

Your right, the Nema17 is pretty small, but it does a nice job for hobby applications, that's just my opinion.
I am also no electrician so there maybe much more to protecting the circuit, but I am sure Diodes are used at least on the motor side. You will also need some big caps but that probably has nothing to do with circuit protection. Anyway, if your going to develop something new I highly suggest using a TFID IC and maybe an AVR so you move away from the DB25 port, most PC's don't have them and using a laptop with Mach3 or EMC to run a machine is always nice.
Again just my opinion, as a consumer that's what I would look for, ideally for a price around $100.

[crob09]

I know there are disappointments with the TB6560 stepper boards and issues with the authenticity of the same driver chips offered for sale on eBay.

But that said, would anyone be interested in genuine TB6560s chips on a properly designed PCB with "REAL" opto isolation, over voltage protection and conservatively rated at 2A@35V.

I'd like to hear your thoughts.

Not trying to be difficult here, just providing my thoughts based on your original question and based on how I understood it.

If you had a single solution like the PCB's found on Ebay and you use TB6560's along with an AVR and TFID IC I would be interested and I am sure other people would be. It has to work with Mach3 and EMC just like the Red and Blue DB25 style PCB's that contain TB6560's, if you're looking for a good alternative to those red and blue DB25 style boards try the one made in British Columbia from SOC.
They already offer your alternative.
Also, for Opto Isolation that's why I suggested Diodes, the TB6560 already handles that to some extent.