Dual or multiple Duet 2 / Duex boards communicating
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The Duet 3 prototypes already handle multiple slave boards, so 15 stepper drivers in total would be no problem (6 on the main board + 3 expansion boards with 3 drivers each). The use of CAN for expansion is completely transparent to the user. However, we have only a few prototype expansion boards at present, and it's likely to be a few weeks before we manufacture another batch of prototype or pre-production boards.
We demonstrated controlling 6 motors locally and 6 over the CAN bus last September at the TCT show. See https://www.youtube.com/watch?v=LaNYeQiZK9M. The motor movements in that video were commanded by ordinary GCode commands.
To connect 2 DueX5 boards to a Duet, you could construct an interface board with three 50-way and one 10-way ribbon cable headers. Then the Duet CONN_LCD and expansion connectors would be connected to this interface board, and the two DueX5 wold also connect to it. Once of the DueX5 would be connected straight through to the Duet expansion bus (so alternatively, you could use one ribbon cable with 3 connectors on it to connect the Duet, interface board and one DueX5 together, and only have two 50-way connectors on the interface board). The other DueX would take some of its signals from the expansion bus and some from CONN_LCD.
You would need to find 9 free microcontroller pins to drive the Step, Dir and CS signals for the last 3 drivers on the DueX. If you are not using temperature daughter boards on either of the DueX, then you can start with the 4 CS signals. If you don't need the two endstop connections on CONN_LCD, that gives you 2 more. But you still need to find another 3 from somewhere.
I could give you help in adapting the firmware, but you would need to integrate future changes into it yourself.
Duet WiFi hardware designer and firmware engineer
Please do not ask me for Duet support via PM or email, use the forum
http://www.escher3d.com, https://miscsolutions.wordpress.com -
PS - I just saw that you need a lot of endstop switches. That makes it harder to do using Duet 2 even with just 15 stepper drivers. The full version with 28 drivers definitely needs Duet 3.
We need some beta testers that use a lot of stepper drivers, so we might be able to spare you a Duet 3 prototype; however the next run of expansion boards will take a few weeks to do.
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Yes I was just reading your previous post thinking we have an endstop for each stepper. We could on some of steppers use stall detection but I'm not sure we could take that to production.
I don't think a few weeks would hurt to wait, currently we have a stack of raspberry pi's/odroids etc handling a few steppers/end stops manually controlled with buttons for testing.
When do you expect the duet 3 goes into full production? Or more important when do you expect it to be available to go into a production device?
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We expect Duet 3 production to start in late Q2 or Q3 this year. We have second-generation prototype Duet 3 main boards already, and we expect the production boards to be almost identical to them.
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That falls in line with our schedule. Do you have a list of supported items for the main board and available prototype slave boards? Depending on what is currently supported in prototype we may have to adjust our prototype to fit and that should be learned sooner rather than later if possible.
Also is there any current weaknesses in functionality compared to the Deut 2 functionality.
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Duet 3 will offer a lot more functionality than Duet 2, although it may take a few months before all of it is implemented in the firmware.
The prototype main board have 6 stepper drivers, 4 thermistor inputs, 10 heater and fan outputs (6 low current, 3 medium current, 1 high current), 9 I/O connectors that can be used to connect endstops, Z probes, filament monitors etc., 1 servo output and one LED strip output. The prototype expansion boards have 3 stepper drivers, 9 heater and fan outputs (6 low current and 3 medium current), and 6 I/O connectors. Both boards also accept up to 2 of our PT100 and thermocouple daughter boards. Multiple expansion boards can be connected to one main board.
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Wow sounds nice.
You mentioned 10 heater and fan outputs on the main board, is that 10 heater and 10 fan or 10 total for heaters and fans?
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10 in total.
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After a couple of very long days I'm not sure what I was thinking asking that question.
How do you suggest we proceed with the duet 3 prototype?
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@jabbery, I'll respond by email.
