More steppers than 10?



  • I know this is going to get some pretty interesting reactions as this is going to sound slightly absurd, but hopefully I can show part of why this might actually be useful, while not talking about my actual reason for asking…

    So, what's the possibility of setting up DuetWifi + Duex5 and then somehow adding an additional 12 stepper drivers beyond that? Yes that means a total of 22 steppers... I wouldn't need additional of anything else as the Duex5 already adds the other heat circuits I cared about.

    Now, ignoring my specific purpose, here's an example of why more than 10 is useful, since I've seen some discussions here saying that anything beyond that would be ridiculous (not that I'm entirely arguing that as what I want to build is kind of an absurd build but it's meant to do some research into a few things). With the addition of automatic bed leveling which appears to be coming now(?) with 4 independent z screws, you're already up to 4 steppers. Now adding simple X and Y for a Cartesian bot you're up to 6. Now if you add the 5 drives needed for the diamond hotend you're up to 11 and already outside what Duet + Duex5 can handle to my understanding. Now if you wanted to add a secondary extruder, for say support material, you're up to 12, now say you actually wanted to do dual diamond hotends? that would require a total of 16 steppers to handle 4 z screws + x + y + 2 diamond 5 way hotends. So without saying exactly why I want 22 stepper drivers, there's some examples where more than 10 would be completely valid and useful.

    I've never personally used a Duet based system, I'm planning a completely custom build, and so poking around at the options as I'm more a software type of person. The upcoming smoothie v2 was interesting due to the potential to chain extruder drivers, but overall I think I'd rather go with Duet, but I can't come close to what I want to do with less than 17 steppers and couldn't do the full build with less than 22. Would there be a way to do chainable expansions like what smoothie is supposedly planning on top of the Duet/Deux5 combo to give additional steppers?


  • administrators

    We already announced that we will support chainable expansion boards in the next generation of the Duet series (project name DuetN^2G). Design work has already started. With Smoothie 2 taking so long, who knows, we may even have it first. Perhaps you want to be a beta tester when we have hardware available?

    For the current generation board, I am considering supporting 2 additional external drivers connected to the CONN_LCD connector. We may manage 3, but after that, we start running out of processor pins. You could multiplex additional external drivers if you didn't want to drive them all at the same time.



  • @dc42:

    We already announced that we will support chainable expansion boards in the next generation of the Duet series (project name DuetN^2G). Design work has already started. With Smoothie 2 taking so long, who knows, we may even have it first. Perhaps you want to be a beta tester when we have hardware available?

    For the current generation board, I am considering supporting 2 additional external drivers connected to the CONN_LCD connector. We may manage 3, but after that, we start running out of processor pins. You could multiplex additional external drivers if you didn't want to drive them all at the same time.

    Somehow missed that.. Glad to hear it should be coming though!

    I would say I'd be happy to be a beta tester but it's likely to be a couple months before I actually build the frame out so I don't really have a good way to be of use at the moment. I just have an off the shelf printer for the moment as to help with building the one I'm planning. If I do get it built before the new hardware is ready then I'd be happy to help! Do you have any guess on timeframe? I'm still in the early stages of planning what exactly I'm going to build so I'm not really in a hurry, just more curious.



  • @Zredok:

    ….............. here's an example of why more than 10 is useful, since I've seen some discussions here saying that anything beyond that would be ridiculous ..............................

    I doubt if you've seen that discussion on these Duet forums - quite the opposite in fact. That's why the designers and developers are already planning for it. I will very shortly have a fully populated Duet plus Duex5 (10 steppers) so can see the need for more in the future.


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