Duet 3 Mainboard 6HC - initial production run.

[minim]

It will be fun to see the improvement but I don't fancy the idea of a SBC at all. I kinda need it for the stepper drivers on nema 23s.. Time will tell if SBC was the correct decision I guess

[A Former User]

I was actually thinking about that the other day, most of the issues can be mitigated by having the system run with the majority of the operating system as read-only under normal operations. I don't know what is planned, but it quite doable to make the Duet 3 image fairly resilient with respect to unexcpected shutdowns.

[Phaedrux]

@leonmf said in Duet 3 Mainboard 6HC - initial production run.:

My experience with Raspberry Pis were that they are a full OS and don't particularly love being shut down without going through a clean shutdown.

I may be lucky, but I have never shut down a pi cleanly. Always just pulled the power on the poor little things. Never had any ill effects.

[DocTrucker]

@phaedrux think this is more like to be a problem if the DWC solution on the computer does some heavy background processing like simulation.

[JoergS5]

@leonmf so maybe it's better to setup the operating system as read-only, similar to http://hallard.me/raspberry-pi-read-only/
and held the non volatile data in a separate storage.

[T3P3Tony]

Good points. One way to go is to have the power configured so the Raspi does not shut down, or at least is in charge of the shutdown. So power off just sets the printer into a low power sleep mode where the 24V is off and only a little 5V is used to keep the Pi idling... When you turn a modern TV or whatever that is what happens...

[dc42]

@knaudler said in Duet 3 Mainboard 6HC - initial production run.:

screws for Power ?
something like this would be nice:
https://www.wago.com/de/leiterplattenanschluss/klemmenleiste-fuer-leiterplatten/p/2716-102

I've taken a look at the Wago range of push-in connectors. Many of them are either too large or very expensive. The most suitable 6-way one I found was this one https://uk.farnell.com/wago/2092-1376/terminal-block-wire-to-brd-6pos/dp/2352417. Like most push-in terminals blocks, it's only suitable for use with solid core wire or stranded wire that has been terminated with ferrules already. So if you need to use stranded core wire, it doesn't avoid the need for crimping, and it's hard to justify the additional cost.

For the home user, an advantage of the barrier strips we currently use is that crimping tools for automotive-style fork receptacles are very cheap. But I can see that some OEMs might prefer push-in terminals to speed up wiring.

[A Former User]

Back in the day, we ended up with a compromise and used pluggable terminals where phoenix contacts had both screw and push-in female connectors, the boards used the same male header (but that was only up to about 10A iirc)

Also found that you could use stranded wire without ferrules, but then you loose the tool-less advantage as you need to press the release spring to insert the stranded wire. And something like Radox 125 is wound so tight it can be inserted without ferrules in a pinch, but for production you'll want ferrules anyways.

But yes, quite significant savings on wiring time with push-in terminals when wiring is prepared by machines automatically cutting, stripping, labeling and crimping ferrules. However unless you have the machines I doubt its worth the investment for a single 6-pin terminal.

[JoergS5]

@leonmf I bought a Pi 3+, but will buy a Pi 4 also, because he has a lot more I2C and SPI interfaces (about 5 each, 3 + has only one useable SPI, which will be used to communicate to Duet), so if one wants to use Pi4 for additional tasks like using cameras (e.g. Arducam with SPI/I2C interface), additional I2C and SPI are useful.

[KP0005]

Regarding the SPI connection, would it in theory be possible to connect a Maestro to the SBC in a similar way?

[dc42]

@matej101 said in Duet 3 Mainboard 6HC - initial production run.:

Regarding the SPI connection, would it in theory be possible to connect a Maestro to the SBC in a similar way?

In theory yes, with a lot of firmware changes. Ideally the W5500 Ethernet chip would be removed to free up the fast SPI connection. I guess the daughter board SPI could be used instead, at a lower speed and by dropping support for external SD card sockets and temperature daughter boards.

[KP0005]

@dc42 thank you for the quick reply! I'm not really experienced with programming so redoing part of the firmware seems to be a bit of a stretch for my use case. Guess I'll just hack something together instead.

[A Former User]

@matej101 said in Duet 3 Mainboard 6HC - initial production run.:

@dc42 thank you for the quick reply! I'm not really experienced with programming so redoing part of the firmware seems to be a bit of a stretch for my use case. Guess I'll just hack something together instead.

No hacking needed just buy a Duet 3..............

[KP0005]

@calvinx but money...

[mundsen]

Order one today, plan to use it in my Corexy project 🥰

[dc42]

@matej101 said in Duet 3 Mainboard 6HC - initial production run.:

@calvinx but money...

It's occurred to me that a Duet Ethernet without the Ethernet daughter board should be relatively straightforward to connect to a RPi. Maybe I'll add support for this in the future.

[gtj0]

@dc42 said in Duet 3 Mainboard 6HC - initial production run.:

It's occurred to me that a Duet Ethernet without the Ethernet daughter board should be relatively straightforward to connect to a RPi. Maybe I'll add support for this in the future.

That could be VERY handy!

[denke]

@dc42
As I remember the wifi can also be converted to ethernet. So, Is it possible for that too?

[dc42]

@denke said in Duet 3 Mainboard 6HC - initial production run.:

@dc42
As I remember the wifi can also be converted to ethernet. So, Is it possible for that too?

Yes, if you removed the WiFi module.

[dc42]

The tests on the first Duet 3 main board have passed over the weekend, so assembly of the first batch is now under way.