Duet 3 Mainboard 6HC - initial production run.

wilriker

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

Is it possible to power the MCU from EXT 5V (to allow it to shut off motors and heaters by turning off the 24V PSU), or has that been replaced by the SBC->5V setup?

That's still possible.

martink

@wilriker Great, thanks for confirming!

Knaudler

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

DocTrucker

@knaudler Potential cost issues apart these are better. No loosening issues as the springs keep the correct loading on the contacts.

LeonMF

I've already bought my board (looking forward to it!). I totally didn't even read the specs before buying so I'm now catching up on the whole SBC thing.

So, with the new SBC interface, does that mean that the PanelDue is deprecated? Is/will there be another touchscreen replacement to fill the gap?

Also, is there any reason to avoid or go for a Pi 4 over the 3+?

Phaedrux

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

Also, is there any reason to avoid or go for a Pi 4 over the 3+?

I just got my hands on a 2Gb Pi 4 and I'm quite pleased with it. The biggest improvement IMO is the change to the ethernet and USB ports. In the Pi 4 you get actual gigabit ethernet speeds and actual USB3 speeds, whereas with the Pi3b+ the ethernet port was hung off the USB hub and shared their limited USB2 bandwidth. It made certain i/o tasks painful.

The big CPU upgrade is nice as well as the added ram. I doubt that will really become critical for running the duet, but given the minor cost disparity, I would say that the Pi 4 will have more longevity, especially if you ever wanted to repurpose it.

wilriker

@leonmf In addition to what @Phaedrux said the requirements have been changed to "RPi 3B or newer" which of course also includes the latest RPi 4B. Maybe the product page has not been updated after that change.

This originally simply was because at the time prototyping tests began RPi 3B+ was the most recent version.

T3P3Tony

@leonmf in addition to the good points about Raspberry pi versions already made, regarding the screen: The idea is that there are a multitude of HDMI and direct interface touch screen available for Raspberry Pi so you have much more choice. at the simplest level you can have DWC running on the touch screen in a maximised browser but i am sure there will be a range of UI options developed to suite different screen and requirements. The advantage of doing this on the SBC is its much easier to make UI changes than on the PanelDue.

LeonMF

Thanks everyone!

@T3P3Tony I had this argument with the M3D team when they argued that the PanelDue was a waste of time.

The PanelDue is certainly limited in what it does and how it operates but that's part of the benefit. Fundamentally, it just works and the M3D argument of buying a cheap tablet and using it as a UI completely missed the point that you just need the ability to poke a jog or home button without the drama of maybe the tablet went to sleep or the UI wasn't built for touch.

But... if you're saying that there will likely be a touch friendly UI that works with the SBC and the SBC being operational is required for the unit then I likely have little to complain about!

LeonMF

Posted in a separate comment for clarity.

Some time ago, I used to run my home automation system on Raspberry Pi. Then, after that, I ran my home audio on Raspberry Pis. They did work pretty well but were more prone to corruption than I'd like.

The beauty of an embedded board like the Duet 2 is that powering it down and back up meant that it was still going to come back up fine.

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. Something that a device with an off-switch isn't all that great for. Perhaps my early experiences with Raspberry Pis reflect a fear about dirty shutdown corruption that isn't a reality any more. Do I have any reason to be concerned on this or are my fears several years out of date?

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?