Breakout Drivers PLEASE



  • I do not have a DuetWifi, however I am shopping for a new board since my Lulzbot Taz 5 has blown (2) drivers on (2) Rambo boards… (using factory issued non modified firmware) I see the Smoothieboard has them. I searched the form and see others already talking about burned out drivers so for now it looks like Smoothieboard will get this order.

    Please make a way that the drivers could be replaced easily that does not require a hot air station.


  • administrators

    If by "breakout drivers" you mean the ability to add external drivers to substitute for any blown drivers on the main board, Duet WiFi does provide that. You connect the replacement driver or drivers (up to 5) to the expansion bus, and use the M584 command in the configuration file to tell the firmware to route the control signals to them. This is more flexible than the Smoothieboard approach because it allows for a total of 10 drivers instead of 5.



  • Also, before you hook up a new board, you might want to check your wiring to the motor(s) that keep blowing drivers. Good luck!



  • @dc42: I think OP means Pololu style stepsticks.

    @OP: From what I understand it is unlikely the Duet will ever do what you're requesting. Actually integrated stepper drivers is better from a heat and reliability point of view - the drivers are designed to sink heat through the bottom of the chip into the PCB. On a Pololu style driver, there is barely any surface area for heat to dissipate. With a Pololu driver you have those pin headers, which can create poor connections that lead to driver failure as well.

    Additionally, the reports of blown drivers are less than ~1% of all boards sold, and generally occur nearly immediately (in which case they are replaced at no charge) or they happen because a user does something like disconnect a motor with the boards powered up (which is bad practice).

    Also there are folks that will repair Duets at reasonable prices, if you do find yourself to be in the ~1%. I run about 1500 hours now on a Duet Wifi, no stepper driver damage. Come to think of it I have about 8000 hours of 3D printing across 7 3D printers and I've never blown a stepper driver.



  • And the Smoothie is exactly the same in this respect to the DUET there drivers are also hard soldered to the Board they just make it slightly easier to use an external driver module by have the input signal brought out to headers but it is not to difficult to do it with the Duet should you need to?

    Doug



  • The blue v1.01 I think it is board appears to have these breakout pins already. Perhaps they are just for test points, but sure doesn't look like it.

    Jeff


  • administrators

    Those points could be used to connect breakout drivers, but as those channels are configured in firmware for TMC2660 drivers, it would require a firmware change to support Pololu-type drivers on those pins. Given that the firmware already supports connecting Pololu-type drivers to the expansion bus, and mapping of XYZ/E1/E2 motors to whatever drivers you want, it seems pointless to complicate the firmware by making the on-board driver type configurable. Also, most Pololu-type drivers also need +5V or +3.3V and you would have to get that from the expansion connector anyway.



  • @dc42:

    Those points could be used to connect breakout drivers, but as those channels are configured in firmware for TMC2660 drivers, it would require a firmware change to support Pololu-type drivers on those pins. Given that the firmware already supports connecting Pololu-type drivers to the expansion bus, and mapping of XYZ/E1/E2 motors to whatever drivers you want, it seems pointless to complicate the firmware by making the on-board driver type configurable.

    This makes sense, also the onboard drivers are IMO far superior to most. No need to complicate things more.

    Jeff


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