New Duex2,3,4,5?
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Ryan, we already have tacho support on RepRapFirmware for the Duet 0.6, including display of the fan RPM in Duet Web Control. The snag is that you need to use 4-wire fans for the tacho output to work. and those fans typically can't run below 30% of full speed. So if you want to control the speed AND be able to turn them right off, you need to switch the supply voltage as well as giving them a PWM signal. Also, 4-wire fans are generally only available in 12V.
It's possible that the tacho output of a 3-wire fan might work if we PWM'd the positive supply instead of the ground connection - I haven't tried that.
The tacho support could easily be included in the Duet WiFi, we just need to assign an expansion connector pin to the tacho input.
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I'm thinking of fan tachs as a "shut off heaters if they're not spinning" safety function. Consider your average PLA effector with an E3D or what have you… If the hot end fan stops, really bad things can happen. I wouldn't do any kind of speed control on it (the standard PWM fan function is fine for that).
Honestly, could just be a pin that acts like a charge pump safety cutoff. Doesn't have to be fan-specific.
Optional stuff either way.
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This is a shameless bump but any update on timescale for Duex2,3,4,5? My printer build is coming along nicely, Duet WiFi is ordered as are the 3 off E3D Titan extruders but I won't be able to commission the beast properly until I can add at least one extra stepper. Then later on, when DC does the firmware to support auto bed levelling, I'll need another 2 steppers. Sorry to nag.
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I'm planning a motor for z, a motor for y, two x motors for dual carriages, and two extruders. It might be nice to clone Y to run two motors instead of a shaft.
7 total for me, Duex2 would work.
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Another shameless bump but I haven't had a response to my last shameless bump of 24th July. So any news regarding Duex (n)? I'm going to need to be able to drive 3 extruders pretty soon now.
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I am actually working on the schematic right now. So far I have the following requirements:
5 TMC2660 drivers (all my not be populated on Duex2/3)
5 heater and thermistor channels (1 high power to use for a chamber heater/dual area heat bed)
Headers to by pass the TMSc and connect external drivers
5 Endstops (to use for filament out etc on each extruder or other purposes).The following are nice to have
5 PWM fan channels
"n" servo channels (1-5? how many?)What else?
Cheers
Tony
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Is some of this easily obtained by hanging a custom board or two off an I2C/SPI pin? Presumably there would be problems using this for realtime applications, but most of these "extra" motors and sensors are much less critical. For that matter I have a Raspberry Pi "hat" that drives a zillion servos over I2C, and I could hook it up to the Duet if it had an accessible pin.
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Yes you can add as many expanders as there are i2c addresses if you want.
What the expansion board will do for the stepper drivers is use existing E2-E6 channels which will be as quick as the on board TMCs.
The fans and servos will be on I2C so not as "real time" although fine for fans, tool changers etc.
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I am actually working on the schematic right now. So far I have the following requirements:
5 TMC2660 drivers (all my not be populated on Duex2/3)
5 heater and thermistor channels (1 high power to use for a chamber heater/dual area heat bed)
Headers to by pass the TMSc and connect external drivers
5 Endstops (to use for filament out etc on each extruder or other purposes).The following are nice to have
5 PWM fan channels
"n" servo channels (1-5? how many?)What else?
Cheers
Tony
Hi Tony,
So it's looking like any sort of expansion board is still a long way off. As soon as my batch4 Duet WiFi arrives, I'll be at the final wiring and then commissioning stage for my new build. However, I can't run the Diamond hot end with only 2 extruders as filament will simply be forced up the unused input and then cause a blockage. So I fairly desperately need to be able to run three extruders (one more than the basic wifi will allow).
What are my options? Do you or any one else fancy knocking me up something that I can plug in to get me up and running with 3 extruders until the proper expansion board is available? It doesn't have to be a proper pcb, just something to get me going. Happy to pay providing the cost is not extortionate. Feel free to pm or email me.
Ian
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Hi Ian.
We can put together a solution using a stepstick and level shifter or similar that will tide you over.
This can be done on stripboard so no need for a proper PCB. Are you comfortable with basic soldering or do you need me to make one up for you?
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Hi Tony,
These days, my eyes aren't what they were, even with varifocals, nor are my hands as steady as they used to be (2 years away from the state pension age). Much as I hate to admit it, I'd prefer it if you could make one up. I appreciate that you'll need paying for your time as well as the parts.
Ian
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The other possibility would be to make a small converter board or even just a cable to convert the Duet WiFi expansion connector pinout to the DueX4 pinout.
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If you just want the third filament to stay put, can you not just arrange a way to fix the filament in place until you get the duexn?
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@bot:
If you just want the third filament to stay put, can you not just arrange a way to fix the filament in place until you get the duexn?
I thought of that but the problem with the Diamond hot end is that normal retraction doesn't work- - all that happens is that it draws filament from an unused input rather than from the nozzle. Therefore, I have to use firmware retraction to retract all 3 filaments simultaneously. So just wedging some filament in place will effectively give me no retraction. The other thing that happens is that, if you don't extrude any filament from one of the inputs for a long time, they become blocked at the heat sink. I suspect it's heat creep, due to heating the filament but not extruding any. Or maybe it's pressure on the "in use" input pushing melted filament back up the "unused" input.
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The other possibility would be to make a small converter board or even just a cable to convert the Duet WiFi expansion connector pinout to the DueX4 pinout.
Er, yes but I don't have a DueX4.
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Ian
No worries, I will get the level shifter ordered and put one together. It wont be mega expensive.
Cheers
Tony
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Any eta on when a Duet Wifi expansion board will be ready for order? I have my Duet Wifi but have not installed it yet as I need to have at least 3 extruders. I would rather not deal with a temporary solution as I kind of have my Azteeg X3 Pro working alright but Marlin is frustrating me. The Atmel processor just isn't fast enough to do everything it should.
I think I will be taking the machine offline to switch from long bowden systems to Flex3Drives fairly soon. While I do that would be a good opportunity for me to swap the Duet Wifi and expansion boards in.
Also, really glad that the Wifi and expansion board have endstops for extruders. Filament present sensor has been one of my planned features for my machine!
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We are working on it right now but I can't give a definite ETA yet. I should have the prototypes ordered next week at which point I will have more clarity and will post an update.
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We are working on it right now but I can't give a definite ETA yet. I should have the prototypes ordered next week at which point I will have more clarity and will post an update.
Awesome to hear. Thanks for the insight!
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One of the features we are considering for the DueX2/DueX5 is an on-board switching regulator to provide a 12V supply when Vin is higher (typically 24V). This would facilitate using 12V fans and 12V LED strips. It would add about £5 to the retail price of the board. Those of you who are interested in expansion boards, do you think this is a good idea, or not worth the extra cost?
