Is there any way to change drivers (TMC2660) to the common A4988?



  • Hello, i´m struggling to convert the expensive TMC drives on duet board for the changeables A4988, for reducing costs and improve maintenance, but, on the TMC uses SPI com to communicate with the ARM. Does anyone had tried this before?



  • Why would you want to convert them? You have to buy the Duet Wifi/Ethernet with the TMC2660s already installed at regular price, so how it save money to take them off and add A4988s in their place?

    What maintenance are you referring to?



  • For make it easy to change then in case they burn, or use different drivers for nema 23, etc



  • https://duet3d.com/wiki/Duet_Wiki
    Isn't it covered in the wiki?



  • They shouldn't burn unless you've done something wrong, and if that's the case and you have the equipment to remove a TMC2660 then you can install a new TMC2660.

    Plus TMC2660s have higher current capacity (2.4A on the Duet Wifi) than a A4988, so a TMC2660 is better suited to NEMA23 than other drivers.


  • administrators

    Pao, plug-in A4988 drivers burn out often because they have insufficient heatsink area, it is very difficult to set the current correctly, and the path from the chip to the decoupling capacitor is too long. Also some people disconnect stepper motors from them with power applied, which sends a large voltage step back to the driver.

    But drivers soldered on to properly-designed boards such as the Duet are much more reliable. This was proven on the Duet 06 and Duet 085 boards, which use the A4982 driver (like the A4988 but in a different package).

    So you should stop worrying about burning drivers on your Duet WiFi - unless you are being extremely careless with your wiring! In fact the TMC2660 drivers are quite tough even if you do abuse them - see the video I posted recently. The main thing they don't like is excessive power supply voltage (more than 30V).

    You can connect external stepper drivers to a Duet WiFi as described at https://duet3d.com/wiki/Using_external_drivers.



  • But dc42, the TMC2660s are too expensive, something like 12x more expensive than the a4988, thats why i´m trying to modificate, even if redesign with wires in the board is necessary. And don´t worry i´m taking care of my Duet Wifi like my baby 😛



  • I just installed a Duet Wifi in one of my printers and the change in quality of prints are quite remarkable compared to the RUMBA with 4988 drivers that I used before. Replacing the drivers with 4988 drivers would be straight up stupid.

    If you want to make your own boards with reprapfirmware, you should stick with the better drivers. Also be aware that setting power through config files would not work for 4988s unless you use DA converters to control the reference voltage on the 4988s, and that would be a major redesign.



  • Perhaps you should consider not modifying the board now, but waiting instead for the eventuality where one fails and you can't get another 2660?


  • administrators

    @Pao:

    But dc42, the TMC2660s are too expensive, something like 12x more expensive than the a4988…

    Assuming you've bought a Duet WiFi or Duet Ethernet board, you've already paid for them!

    They are more expensive because they are much, much better. And the chips are not 12x more expensive than A4988s, more like 2 to 3x. Digikey UK sells them individually at less than £5+VAT each.



  • @dc42
    I bought A4988 from AliExpress and is much much cheaper than TMC2660

    • 10 pcs cost £7 incl delivery (£0.7 each incl delivery)
    • 30 pcs cost £16.8 ( £0.56 each) + delivery cost (£3) for 30 pcs

    The TMC2660 cost
    -10 pcs £45 ( £4.5 each) from Digikey

    But, of course the TMC2660 are much better than A4988.....



  • @Pao de Forma,

    Stop being an idiot and you won't have to replace it with an inferior driver chip. If you have enough skills to solder and replace the TMC2660 chip with a A4988 driver and update the firmware yourself, you won't even have to ask the question in this forum. Stop wasting DC42's time and let him work.

    If you really want a challenge, replace the core i9 extreme CPU on an Intel board with an 8088 CPU. It will keep you busy.



  • If I had the power to lock, or better yet entirely delete, this thread, I would.

    Pao, STOP WASTING EVERYBODY'S TIME. The idea you are pursuing is as "off topic" to the philosophy of the Duet series of boards as it is possible to get. They are high end boards, and high capability. The idea of DOWNGRADING part of the board, to save less than £4, in a circumstance that is very unlikely to happen to begin with... that idea is directly opposite where the company, and the customers of the company, want to go.

    Please, go purchase a rock bottom priced board and get on THEIR forums. Leave us alone.

    Go away.



  • And this children is why birth control was invented.


  • administrators

    @electra said in Is there any way to change drivers (TMC2660) to the common A4988?:

    @dc42
    I bought A4988 from AliExpress and is much much cheaper than TMC2660

    • 10 pcs cost £7 incl delivery (£0.7 each incl delivery)
    • 30 pcs cost £16.8 ( £0.56 each) + delivery cost (£3) for 30 pcs

    The TMC2660 cost
    -10 pcs £45 ( £4.5 each) from Digikey

    But, of course the TMC2660 are much better than A4988.....

    Quite so. People buy the Duet WiFi because they are looking for something better than Arduino Mega+RAMPS+A4988.

    Btw it's possible to connect A4988 or other drivers to the expansion bus. This is covered in the wiki page about connecting external drivers.



  • @dc42 said

    Quite so. People buy the Duet WiFi because they are looking for something better than Arduino Mega+RAMPS+A4988.

    Exactly!



  • Although I agree with the sentiment, I'm curious as to why people are now giving "Pao" such a hard time. His last post was 19th May 2017. Why resurrect a year old thread to tell someone to go away when he in fact went away a year ago?



  • @deckingman said in Is there any way to change drivers (TMC2660) to the common A4988?:

    Although I agree with the sentiment, I'm curious as to why people are now giving "Pao" such a hard time. His last post was 19th May 2017. Why resurrect a year old thread to tell someone to go away when he in fact went away a year ago?

    looks like the thread was resurrected by elektra, and it kind of ran away from there..... all sentiments still stand a year later.



  • As mentioned, were I a moderator, this would be a "Delete".

    So that it can't pull itself out of the grave, again...



  • Maybe not delete but certainly lock so that no further comments can be made


 

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