duet3 and e3d ToolChanger and Motion System

dc42

The reason we chose 3 for the first expansion board is that in a single CAN message we can fit the parameters for 3 stepper drivers.

A Former User

@dc42 said in duet3 and e3d ToolChanger and Motion System:

single CAN message

hm, I missed this, need to go check D3 schematic .. so extension boards for D3 are on can bus, not dir/step like on D2 ? interesting, I always wondered how they sync movement of can bus drivers without a "start / clock" line

dc42

@smece said in duet3 and e3d ToolChanger and Motion System:

interesting, I always wondered how they sync movement of can bus drivers without a "start / clock" line

The main board periodically broadcasts its time (in ticks since start-up, where 1 tick is 1.33 microseconds) and the expansion boards use this to convert the start times of incoming movement commands to their local tick count.

A Former User

@dc42 so you broadcast "local time" so that all modules can sync their time, and you send step commands (start at time X, do Y steps at speed Z ?? ) .. or you fill some "registers" on the dbus client that converts to commands? I have some tiny, tiny experience with MESA cards on ethernet and even less experience with modbus drivers...

dc42

The main board sends the specification of the move. This is the scheduled start time, number of ticks for acceleration, number of ticks at steady speed, number of ticks for deceleration, start speed percentage of top speed, end speed percentage, number of microsteps for each drive, and which drives have pressure advance applied. The move specifications are sent about half a second before they are due to start.

A Former User

@dc42 cool, I'll check out the firmware to see how it works, I should have some time during holidays (for us xmass is in january so tomorrow the party starts and ends in mid-january ) to use to get acquainted, expect questions

anyhow, a friend just surprised me with a duex5 (a prc clone he purchased and never used) so I'm fully covered till duet3 expansion board is ready for me to order them both

one additional question, how does the thermal sensing work on d3 + expansion? I have some semitec ntc's that go up to 300C that I love to use as I know them good and have ton of them (I needed exactly them for some project 9-10 years ago and semitec wanted to sell me only 300pcs and I needed 2 ) so I'm using them everywhere, I think I still have ~50 of them .. I know a lot of ppl go for PT100 but I paid arm and a leg for these ntc's I wanna use them everywhere I can

dc42

@smece said in duet3 and e3d ToolChanger and Motion System:

one additional question, how does the thermal sensing work on d3 + expansion? I have some semitec ntc's that go up to 300C that I love to use as I know them good and have ton of them (I needed exactly them for some project 9-10 years ago and semitec wanted to sell me only 300pcs and I needed 2 ) so I'm using them everywhere, I think I still have ~50 of them

If they are 100K NTC thermistors then reading them up to 300C will be no problem on either the main board or an expansion board.

A Former User

toolchanger arrived, I ordered a duet2eth+duex5 from e3d for now to get everything working and I'll go with 3 when expansions are avaialable .. no motors here need more than 24x2 so I think this will be ok for now

Danal

@smece said in duet3 and e3d ToolChanger and Motion System:

with 3 when expansions are avaialable

Wait for toolboards.

A Former User

@Danal said in duet3 and e3d ToolChanger and Motion System:

@smece said in duet3 and e3d ToolChanger and Motion System:

with 3 when expansions are avaialable

Wait for toolboards.

what are toolboards?

Danal

Toolboards are somewhat like a 3HC expander, except they are physically smaller, and have one of everything. One stepper driver, one heater mosfet, one thermal sensor input (actually, a couple), two fans (heatbreak and part), a few general I/O, and so forth. They are CAN attach.

Therefore, your tool changer can have two power wires, and 4 CAN wires, running to each tool. Instead of 10 or 12 wires.

Tool boards are currently in final beta, to be pre-order in the next couple of months, and general order soon after that.

https://duet3d.dozuki.com/Wiki/Duet_3_Tool_Board

A Former User

@Danal said in duet3 and e3d ToolChanger and Motion System:

and have one of everything.

assumed so but was unable to find the link coooooool ... definetely no reason to rush with d3 order, d2 will get the job done more then adequate and then I can move to d3 ... knowing myself I'm going to now dump my major test system and make something between my cubebot and this toolchanger but so far I dislike the corexy.. we'll see with bit more time with toolchanger maybe it grows on me .. currently my cubebot is operating with 2 independent X axes but will see how corexy shows up in real usage and how this new head changer thingy shows up before I decide to move on to new build... I surely have another 7-8 months to play with it before I can start making anything new (on some huge project attm that's supposed to be done before september, so ideal time to use TC as is without "improving" it ) ...

anyhow what's much more interesting to me is the whole synchronous CAN movements, need to get that out of the firmware, as I had serious issue making something like that (over modbus but same thing) last year for some project, I had to introduce the "trigger" line and changed the "standard" modbus to some ugly custom monster I'm really not happy with.. and it was 2 axes only!!! so I'm stealing the ideas from RRF as soon as I .... (I did take a peek in the source and it's not "my way of doing things" so it will take bit more time to figure everything out but hey.. that's why we do share the source so we can all learn )

A Former User

@Danal hm, who's designing this tool board, I'd love to make some changes :D... I was planning to make one "huge board" out of duet2 + duex5 + "some upgrades" but looking at this concept now I like it more with a ton of can slaves and fewer wires .. but I'd love some "minor" changes to make it more versatile

deckingman

@smece said in duet3 and e3d ToolChanger and Motion System:

@Danal hm, who's designing this tool board, I'd love to make some changes :D... I was planning to make one "huge board" out of duet2 + duex5 + "some upgrades" but looking at this concept now I like it more with a ton of can slaves and fewer wires .. but I'd love some "minor" changes to make it more versatile

Like all of Duet's products, I'd imagine that the design is based on what end users want or have asked for. I'd also imagine that because Duet 3D is a business, their design decisions will be based on the potential sales volume of units. In which case, I'd also imagine that OEMs will have far more influence than us single users. There is of course nothing to stop you from contacting the Duet team with your design change requests. But if what you ask for is something that will only suit a single user, I doubt very much that it would be put into production.

A Former User

@deckingman I think it would benefit all, but I'm more in the "lemme get my hands on kicad files and gimme few hours " (I do prefer altium, as that one I know how to use, kicad is still not my forte but, better than eagle anyhow ).. and it's rather small changes, nothing serious, but important for me (and possibly others)

dc42

The v1 tool board design is frozen and we are testing the first pre-production ones this week. We are responsive to user needs, so please us know what additional or changes features you would like. Bear in mind that it's impossible to produce a single design that's perfect for everyone. Also, a single-tool board must be small and reasonably priced.

A Former User

@dc42 said in duet3 and e3d ToolChanger and Motion System:

The v1 tool board design is frozen

Ah, /me late again

perfect for everyone ... reasonably priced.

The changes I have in mind are mostly on the pcb side that can probably be implemented without changing pcb dimensions and should not change the price of the board .. but I don't see any schematic/pcb on the https://github.com/T3P3/Duet.git repo? am I looking at the wrong place? otherwise, I'd first make changes and sent them as a suggestion

most of the "changes" I'd make would be adding few headers, I really hate that none of the boards use the 8 external diodes, with the cheap 8 diode protection board in pololu header format, I'd for e.g. love to have a pololu header on the board over the existing driver, this way I can easily add 8 diode protection as add on, also if driver blows I can easily remove it and push in another on in to the header ... as while removing the no-legs chips is super simple with hotair and some minor experience, replacing it is a hassle so that header would be useful...

second header I'd add is a jtag for the arm, not a full .1" header but something small, for e.g. non tented vias that I can push pogo pins to to access the arm directly if need be..

probbly few more things but without schematic and board design impossible to say, all I managed to see is the grayed image showing available connectors and dimensions

dc42

@smece, I have seen no evidence that the 8 external diodes do anything useful at all. Seeing that the stepper drivers already have similar diodes integrated, I very much doubt that they do anything useful, apart from increase the output capacitance. That might just possibly be useful when using Pololu drivers, but not on Duets, which have output capacitors built in.

The board already has a SWD connector, so it doesn't need JTAG.

A Former User

@dc42 said in duet3 and e3d ToolChanger and Motion System:

@smece, I have seen no evidence that the 8 external diodes do anything useful at all.

I did :D, first with Toshiba drivers, then with TI drivers. Tested TMC2130, also helps ... first EMI, tested with old nema23 motors (different ones, I have 100+ of those that I collected over the years), measure interference around the printer and those 8 diodes lower it significantly .. 3dB at least with TMC and over 5dB for Toshiba .. second, kill the motor wire while spinning, 8 out of 10 times driver dies without those diodes, with diodes I'm yet to see dead driver from motor connector shaking lose or pinched motor wire .. so they do help.. major thing I noticed is they help immensely to stabilize ADC input (not a big deal on 3d printers but I use steppers for some chemistry equipment and that noise on adc is super problematic) ...

again, I would not add the diodes on board, just add header so you can push them in if you have use case for it...

also, step/dir/enable + spi pins for driver configuration, on "any" header so one can hook external stepper driver... I don't have a problem to desolder the TMC from the board and hook my gecko stepper or siemens or even xinje servo driver .. I'm talking headers only, nothing else

The board already has a SWD connector, so it doesn't need JTAG.

that's cool, I haven't seen that on the images I found ..

Danal

@smece said in duet3 and e3d ToolChanger and Motion System:

and this toolchanger but so far I dislike the corexy.. we'll see with bit more time with toolchanger maybe it grows on me

Take a look at Jubilee. It is E3D toolchanger compatible (spacing of kinematic lock, etc) and designed to use plastic parts in many places that E3D uses metal. Because of wear, it uses a rather subtle and clever torque sensor on the tool lock. It also has a good implementation of CoreXY, with all the places that need to be precise in that geometry correctly engineered to be precise. Anyway, take a look. Right now, it is my tool changer of choice.

@smece said in duet3 and e3d ToolChanger and Motion System:

what's much more interesting to me is the whole synchronous CAN movements

Duet 3 movement commands are not synchronous. That would be a train wreck on a shared bus.

Moves are sent approximately 1/2 second before they are scheduled. Each phase of the move (start, accel, const speed, ramp down, etc) is sent in 'ticks' and periodic messages on the bus keep all boards in tick sync.

Much, much, simpler and more effective.