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  1. #1
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    Dec 2012
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    tb6560 driver issues

    Hello,

    this project is my first time working with steppers and drivers for them, so I ran into a bit of trouble. I bought these tb6560 chips and made my own pcb with them. I am suppose to send control data from an Arduino to it.
    I leave the motors disconnected and measure the output: it does the stepping procedure correctly. But when I connect the motors, they block (can move them with the hand no matter how hard i try) and make a hummm noise, and the voltage on them (the outputs of the tb6560) are a constant 1 to 2 V, no change, no stepping... It also sucks a lot of current (3A for one motor.)
    I tried 2 motors, NEMA 17, one 0.7A 1.8V, one 1.8A 1.7Ohms, and the same thing happens. I'm also afraid i will burn my arduino or something... the board i made is really simple, no protection or anything, the application in itself is very simple, I don't need microstepping or all the other advanced stuff the chip can do.
    The motors work ok using a L298, again controlled by an Arduino and powered from the USB.

    From what I read, the only things I did that might cause problems would be the facts that I connected the sense pins to ground (but others did it and it works for them...), and that I connected the reset and enable pins to 5V (so the startup sequence might not be respected - check the tb6560 datasheet)

    Any ideeas of what I am doing wrong? Any solutions?
    Here you can find the eagle files:
    http://sdrv.ms/WLa5MW

    Thank you

  2. #2
    Join Date
    Jan 2005
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    1695
    I don't have eagle installed. Can you post a pdf or image?

  3. #3
    Join Date
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    Quote Originally Posted by alkalin View Post
    From what I read, the only things I did that might cause problems would be the facts that I connected the sense pins to ground (but others did it and it works for them...), and that I connected the reset and enable pins to 5V (so the startup sequence might not be respected - check the tb6560 datasheet)
    The chip can't regulate the current if you connect the sense pins to ground.
    Do you rely on the load (motor) to do this?
    Would love to see a link to those "others".

    I don't have eagle neither, please post the schematic as a PDF.

  4. #4
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    Dec 2012
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    http://sdrv.ms/Us8603
    that is the schematic.

    the board: http://sdrv.ms/Xzgvno

    example of others: The TB6560 and Arduino « Giant Pong – Making of.

    What do you mean do I rely on the motor to do the regulation? Is that a rethorical question, or can the motor do that?

  5. #5
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    Jan 2005
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    The chip cannot regulate the current if the sense pins are grounded, it doesn't see current and will remain on, current will rise to maximum only limited by the resistance of the motor.

    Your motor: 1.8A 1.7Ohms needs a 3V supply without current regulation, anything higher will overheat and/or burn the motor.

    This configuration disables all the chip features like microstepping, torque control.. as these rely on it's current regulation capabilities. It degrades the chip to a simple H-bridge.

    Why do you want to change from a L298 to TB6560?

    The author of the article in your link doesn't explain much: why like this, benefits...

    One comment: don't do it like this.
    Either use what you have or use the TB6560 for what it's designed.

  6. #6
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    Dec 2012
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    Choosing between l298 and the tb is not the issue here. I dont have the l298, plus it needs a lot more external components, plus it is not a stepper driver.

    So i need the resistors. What value (for example for the 1.8 amps motor i would need 0.27 ohms), and what power ratings?

  7. #7
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    Dec 2012
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    ok so i added the resistors. But htere is another issue.
    using a 12V source, it only works when I pull up both TQ1 and TQ2 (weak excitation - 20% amps). If i go 50 % or full out, the motor just buzzez and humms and goes crazy. What is the problem now?

  8. #8
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    Dec 2012
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    and the measured voltage with a regular ohmmeter on the motor is +- 0.6 V . But i guess that is because it does the pwm (that is how it does its chopping right)?

  9. #9
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    Your power supply is too small. It cannot supply the necessary current.

  10. #10
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    Dec 2012
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    omg you are right, I forgot I am testing with a small transformer. That is probably it!
    I want to remake my board. Do you have any suggestions of a tb6560 driver board that i can find on the net and use (minimum configuration)?

  11. #11
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    Jan 2005
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    I haven't looked at 6560 boards. They're too weak for any of my motors. Most of them contain serious design faults, but they're fixable.

  12. #12
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    Jan 2005
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    I used the TB6560 single axis boards without problem on my mill drill conversion. There is a picture of the boards I used in the link below. There is a description of a modification I did to the driver to allow the power up sequence to be correctly sequenced. I eventually modified 2 of the drivers and they ran fine. I left the 3rd unmodified to see if it actually would blow. It never did. I sold that machine and before I sold it I put 2 more unmodified drivers back in the control box. I kept the modified drivers to use on my lathe whenever I get around to doing that conversion. The modification worked fine but was kind of hacked. I had absolutely no problems with the particular TB6560 drivers I used either with or without the modification and I ran that machine quite a bit before it got sold. Your mileage may vary.

    Here is the link to the other post I mentioned
    http://www.cnczone.com/forums/1102517-post527.html

    and here is one of them for sale on e-bay right now.
    http://www.ebay.com/itm/TB6560-3A-st...item1e71b9174a

  13. #13
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    Is it ok if I connect enable and reset pins directly to 5V and thus have no contorl on them?
    What would be the implications?

  14. #14
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    Jan 2005
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    Reset and enable need a delay for the 5V to stabilise, directly to +5 will further degrade the already complicated power up sequence.
    You really need a resistor and capacitor to create this delay.

    I have a PCB design and some PCB's left, these are intended for personal use but might very well never be used.
    You can see a picture of an assembled unit here:
    http://users.skynet.be/ldt/CNC%20ele...B6560_assy.jpg

    You could use this one and populate only the parts wich you need now but keep the option of adding more if needed in the future.

  15. #15
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    Dec 2012
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    ok so here is my next problem:
    i remade the board, the schematic I used is here:
    http://sdrv.ms/TBEmhD
    I made it after the schematic here:
    Toshiba TB6560 bipolar controller

    the only modofication: reset is connected directly to 5V, and there is no resistor and capacitor to it...
    I made the board and tested it, and without the motor attached it did the steps ok (i measured the outputs with a multimeter - so i dont think the problem is with the reset pin). When I connected the motor it did that trembling and humming again. Only this time it wouldn't work at all, even at 20% torque. And now the source had enough current for it.
    Then i think I blew my chip. I dont remember what i was doing precisely, but now one of the output pins is internally shorted to Vin, and when I give the chip Vin, GND, and 5V, I sucks tons of amperes. (so I'm pretty sure it's burned, just need confirmation)

    The thing is I would buy another chip and try it again only if I was sure it is going to work. I've been struggling with this for so long now... and the holidays are here...

    Any suggestions, ideas?
    Maybe tell me what chip would be better / more stable to work with?
    Thanks

  16. #16
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    Jan 2005
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    Your schematic is missing basic elements such as decoupling. It won't work. If you are new to electronics, you should copy a working circuit without modification. Simplification is not a good idea unless you understand the possible effects.

    Why not buy the board 109jb linked to on the previous page? It will save you a lot of time and is not expensive.

    The easiest way to destroy a chip is to connect or disconnect a motor with the power applied. Also, according to the 6560 datasheet, the chip will be damaged if you do not sequence the power supplies properly. In other words, you must switch the high voltage off before switching the 5v.

    Much better chips to use are the thb6064 or the tb6600. They do not require power supply sequencing and can handle more voltage and current.

  17. #17
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    ok I did that, connecting and disconnecting the motor while running...

    I'm not buying a driver because this is a school project and I am required to build one.

    I did copy the schematic from the link I sent you (argh, except for the resistor and capacitor an the reset pin - but that was because I dont want to use the reset pin, it will always be high). But like I said, before it worked with 20% torque. Then I redid the board, and it didn't work anymore.

    I am thinking about changing the chip... like I said I dont need much intelligenec from it, just to run 2A motors.
    What about the l297+l298 option? Any up/ downsides I should know about?

  18. #18
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    Jan 2005
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    Your circuit is missing the .1u on the 5v supply. That is important. The chip could malfunction and possibly self destruct without it. It worked before because the old power supply was too weak to cause any damage.

    Why don't you want to use the chips I recommended? They are unquestionably the best chips out there and are easier to use than the 6560.

    The 297/298 are old fashion. No one in their right mind would use them today.

  19. #19
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    Dec 2012
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    the 5V is regulated by the Arduino (what i use to send control signals).
    I cannot find the chips you recommended on farnell or tme.eu. I am in romania, so i cant use them f I can't get them...

  20. #20
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    Jan 2005
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    They are available on ebay.

    The 6560 will work if you follow the instructions I gave.

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