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Duet 0.8.5 Released

Posted by T3P3 
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T3P3
Duet 0.8.5 Released
August 06, 2015 09:20PM
Hi All

I have published a blog post about the new version of the Duet electronics that supports dual extruders on board (or up to 6 extruders with the Duex 4)

Duet 0.8.5 Blog Post

Let me know what you think!

DuetWifi.: advanced 3d printing electronics
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Viper97
Re: Duet 0.8.5 Released
August 07, 2015 10:01AM
I'll be following this... looks interesting.
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Koenig
Re: Duet 0.8.5 Released
August 09, 2015 02:01AM
Quote
Viper97
I'll be following this... looks interesting.

Me too!

Does this: "E1 motor current controlled by the SAM3X8E DAC0 channel" mean that you can dynamically control the current to the stepper,
like using a larger current for quick accelerations (retractions) and a smaller one when there is normal movement to prevent the extruder from grinding into the filament?

If so, that is a feature worth upgrading for.
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dc42
Re: Duet 0.8.5 Released
August 09, 2015 03:26AM
Quote
Koenig
Does this: "E1 motor current controlled by the SAM3X8E DAC0 channel" mean that you can dynamically control the current to the stepper,
like using a larger current for quick accelerations (retractions) and a smaller one when there is normal movement to prevent the extruder from grinding into the filament?

If so, that is a feature worth upgrading for.

All the stepper motor currents can be set in software for all versions of the Duet. Currently, the only uses made of this are to set the stepper motor currents using the M906 command (usually does just once at startup, but you can do it any time), and reducing the stepper motor current when the machine is idle.

Adjusting the extruder motor current as you suggest is an interesting idea. I was using th 5:1 geared extruder with a 48mm long high torque high inertia motor, and I found that if I set the current low enough so as to not grind the filament when the nozzle got obstructed, then I could not achieve sufficient acceleration for the standard load/unload filament commands in the web interface to work. I solved it by changing to 3:1 gearing and a short motor with lower inertia. I didn't think of adjusting the current dynamically.


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Koenig
Re: Duet 0.8.5 Released
August 09, 2015 03:47AM
Quote
dc42
Quote
Koenig
Does this: "E1 motor current controlled by the SAM3X8E DAC0 channel" mean that you can dynamically control the current to the stepper,
like using a larger current for quick accelerations (retractions) and a smaller one when there is normal movement to prevent the extruder from grinding into the filament?

If so, that is a feature worth upgrading for.

All the stepper motor currents can be set in software for all versions of the Duet. Currently, the only uses made of this are to set the stepper motor currents using the M906 command (usually does just once at startup, but you can do it any time), and reducing the stepper motor current when the machine is idle.

Adjusting the extruder motor current as you suggest is an interesting idea. I was using th 5:1 geared extruder with a 48mm long high torque high inertia motor, and I found that if I set the current low enough so as to not grind the filament when the nozzle got obstructed, then I could not achieve sufficient acceleration for the standard load/unload filament commands in the web interface to work. I solved it by changing to 3:1 gearing and a short motor with lower inertia. I didn't think of adjusting the current dynamically.

So you mean that such a feature could be implemented in the 0.6 version of Duet as well?
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dc42
Re: Duet 0.8.5 Released
August 09, 2015 04:22AM
Quote
Koenig
So you mean that such a feature could be implemented in the 0.6 version of Duet as well?

In principle, yes. But I can see a practical problem. Except for the first move in a sequence, new moves are kicked off in the step interrupt service routine. Setting the currents on the XYZ and E0 motors requires an I2C transaction. This is a blocking operation, so it should not be done from within an ISR.


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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T3P3
Re: Duet 0.8.5 Released
August 09, 2015 06:00AM
All versions of the Duet use a MCP4461-103E 4 channel digipot to set the current on X,Y,Z and E0 stepper channels. The MCP4461-103E is an I2C controlled chip and as DC42 points out I2C is not something you want to be using inside an ISR. On the Duet 0.8.5, rather than add another digipot chip for 1 more stepper channel I used the DAC0 output from the chip (once again DC42's idea!). I have not played with the analogue write commands for a DAC channel to see if they are suitable to use in an ISR however they may be so using the DACs for dynamic current control could work.

DuetWifi.: advanced 3d printing electronics
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woo
Re: Duet 0.8.5 Released
August 09, 2015 05:17PM
beautiful!
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o_lampe
Re: Duet 0.8.5 Released
August 10, 2015 02:08AM
I´m sure the chip has two DACs, would it be possible to control both extruder driver currents through them?
It wouldn´t make much sense, if only one extruder was able to retract fast....
Maybe in 0.8.6 version grinning smiley
-Olaf
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T3P3
Re: Duet 0.8.5 Released
August 10, 2015 03:40AM
It does, we shall see if there is any practical improvement in performance using the DAC!
Reply Quote
o_lampe
Re: Duet 0.8.5 Released
August 13, 2015 02:27AM
Will we see a Duet or Duex4 board with DRV8825 or other 1/32 drivers? There are rumors, that the DRV drivers have problems with skipping steps at slow speed. ( If I understood correctly )
But the benefit of 32 or more microsteps is a strong argument for the smoothiboard , MKS SBase or RADDS. IMHO, it´s mostly Daves SW-fork, that keeps people using the Duet. ( No offense ) smiling smiley

Would it be possible to run a delta completely from an "upgraded" Duex4 board, eg. with DRV drivers?
-Olaf
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dc42
Re: Duet 0.8.5 Released
August 13, 2015 03:06AM
On a delta you will get more benefit from using 0.9deg stepper motors than from using 1/32 microstepping. I believe T3P3 considered using the DRV8825 for the new Duet but were put off by the known issue at low currents.

I am planning to add support for drive remapping to the firmware soon, which will allow external drivers to be used.


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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T3P3
Re: Duet 0.8.5 Released
August 13, 2015 03:36AM
Olaf

Yes as David said did not want to tue people to the DRV 8825 as it is known to have a few issues when used for 3d printing. We have supported a number of customers now who want to use the expansion header for driving the movement axis and the on board steppers on the duet for the extruders (for large format printers rather than for 32 micro stepping). In these cases so far we have modified the firmware which works fine, David's planned drive remapping would be even better.

On a separate note I am considering a Duex4 with plug in stepstick format drivers.

Cheers

Tony
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o_lampe
Re: Duet 0.8.5 Released
August 13, 2015 06:18AM
Quote
T3P3
On a separate note I am considering a Duex4 with plug in stepstick format drivers.
Yeah, Christmas gifts in August grinning smiley
As long as the stepsticks will have the digipot-current trimming, I´m your first customer for such a board...
-Olaf
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T3P3
Re: Duet 0.8.5 Released
August 13, 2015 07:11AM
Well the reason for doing a Duex4 with pluggable drivers would be to allow use of the DRV 8825s in stepstick format - but those have a trimppot on the boards for current control.
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dc42
Re: Duet 0.8.5 Released
August 13, 2015 08:26AM
Quote
T3P3
Well the reason for doing a Duex4 with pluggable drivers would be to allow use of the DRV 8825s in stepstick format - but those have a trimpot on the boards for current control.

When I was designing a low-cost 32-bit board with plug-in drivers, I was going to use a 9-pin socket strip on the input side of the driver socket instead of the usual 8-pin strip, with the extra pin being at the end where the pot normally is, and carrying the reference voltage from the DAC. That way, you could remove the pot from a standard stepstick-type driver, solder a 9-pin header strip on that side instead of 8-pin, and connect the extra pin to where the pot wiper used to be. Hence a plug-in driver with digital current control. But the board would accept regular drivers too.


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Viper97
Re: Duet 0.8.5 Released
October 27, 2015 12:22PM
I'm getting ready to pull the trigger on this... has anybody worked with the board and a Prusa I3? I'm curious as to if there were any problems and what I might need to wrap my head around to make this work! (I know, it's overkill but cheap RAMPS is making me rather testy in my old age.)
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T3P3
Re: Duet 0.8.5 Released
October 27, 2015 12:36PM
We have not used it on Prusa i3, however we use it on Mendel90 Cartesian printers and from a point of view of what the printer controller needs to do they are similar.

It is pretty much a drop in replacement for the RAMPS from a hardware perspective, with the one exception of not having control for a servo actuated probe. The advantages and key difference is the Firmware philosophy of everything being set by GCodes, either through config.g or supporting files. That means than you don't need to recompile the firmware or save settings to EEPROM as all settings are stored in text files on the SD card as Gcodes. I highly recommend you use the Web Interface to interact with the firmware - this runs in any modern browser and is more powerful than pronterface style serial over usb control you will be used to for RAMPS.

Cheers

Tony

DuetWifi.: advanced 3d printing electronics
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dc42
Re: Duet 0.8.5 Released
October 27, 2015 01:18PM
Quote
Viper97
I'm getting ready to pull the trigger on this... has anybody worked with the board and a Prusa I3? I'm curious as to if there were any problems and what I might need to wrap my head around to make this work! (I know, it's overkill but cheap RAMPS is making me rather testy in my old age.)

There should be no problem running a Prusa i3 from a Duet, you just need to get the config.g file right. See [reprap.org]. The endstop switch connections on the Duet are different - if you are using microswitches then they need to be connected to the outer 2 pins of the 3-pin connector. As Tony says, there is no support for servo-deployed Z probe, but you can use my differential IR sensor, or an inductive or capacitive sensor - just make sure that you don't feed more than 3.3V into the input on the Duet unless it is via a 10K or greater value resistor. Also the Duet does not support the usual monochrome LCD displays, but it does support the very nice (but more expensive) PanelDue colour touch screen (full disclosure: I designed and manufacture it).


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Viper97
Re: Duet 0.8.5 Released
October 27, 2015 01:24PM
Quote
dc42
[There should be no problem running a Prusa i3 from a Duet, you just need to get the config.g file right. See [reprap.org]. The endstop switch connections on the Duet are different - if you are using microswitches then they need to be connected to the outer 2 pins of the 3-pin connector. As Tony says, there is no support for servo-deployed Z probe, but you can use my differential IR sensor, or an inductive or capacitive sensor - just make sure that you don't feed more than 3.3V into the input on the Duet unless it is via a 10K or greater value resistor. Also the Duet does not support the usual monochrome LCD displays, but it does support the very nice (but more expensive) PanelDue colour touch screen (full disclosure: I designed and manufacture it).

By microswitches you mean the standard switch and not the Sainsmart style with the LEDs I'm assuming? (Which makes sense to me but as I've stated I'm old and sometimes need to double check my understanding of things! winking smiley )
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dc42
Re: Duet 0.8.5 Released
October 27, 2015 01:34PM
Yes, I mean standard microswitches with 2 wires connected, normally configured as normally closed. If you have a 3-wire microswitch board instead, the pin connections will also be different, also you should make sure that they are compatible with the 3.3V supply voltage used by the Duet.


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Viper97
Re: Duet 0.8.5 Released
October 27, 2015 01:41PM
Ah.. good point... I had forgotten the voltage difference. Might be a good time to go optical. Or just switch to straight up micro switches as I do have a set lying about. Thanks.
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o_lampe
Re: Duet 0.8.5 Released
October 28, 2015 03:57AM
Quote
T3P3
I highly recommend you use the Web Interface to interact with the firmware - this runs in any modern browser

...as long as it's Chrome or Firefox smiling smiley
-Olaf
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dc42
Re: Duet 0.8.5 Released
October 28, 2015 04:24AM
Quote
o_lampe
Quote
T3P3
I highly recommend you use the Web Interface to interact with the firmware - this runs in any modern browser

...as long as it's Chrome or Firefox smiling smiley
-Olaf

I am told that it works with Safari too. It doesn't work with IE or Edge.

Edited 1 time(s). Last edit at 10/28/2015 04:24AM by dc42.


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Viper97
Re: Duet 0.8.5 Released
October 28, 2015 09:15AM
Quote
dc42
Quote
o_lampe
Quote
T3P3
I highly recommend you use the Web Interface to interact with the firmware - this runs in any modern browser

...as long as it's Chrome or Firefox smiling smiley
-Olaf

I am told that it works with Safari too. It doesn't work with IE or Edge.

I'm feeling a little MS hostility! I hate Firefox and Safari.... Chrome I use infrequently. Ah... such is life.
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dc42
Re: Duet 0.8.5 Released
October 28, 2015 12:37PM
It's not hostility towards MS, it's that the MS browsers are less good at supporting HTML5 than Chrome and Firefox. See [html5test.com].


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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o_lampe
Re: Duet 0.8.5 Released
October 29, 2015 04:26AM
It works with chrome, but not on a android-platform?

I was looking for a 7-8" tablet PC to be used as display and for small slicing jobs. Maybe the integrated camera could act as remote surveillance cam.

But the windows tablets are more expensive than androids...
-Olaf
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dc42
Re: Duet 0.8.5 Released
October 29, 2015 05:16AM
I use the RepRapFirmware web interface with Chrome on Android occasionally, and it works OK for me


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Viper97
Re: Duet 0.8.5 Released
October 29, 2015 07:02AM
Okay... someone in England just got notified of my order. I went through the coding yesterday on the wiki as well as the blog. I thought I saw a set up for a Cartesian printer (example config) but now I can't find it. Guess I'll dig around a bit and see if I can find it again.

Looking forward to playing with this... thanks for making it!
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dc42
Re: Duet 0.8.5 Released
October 29, 2015 08:09AM
Quote
Viper97
Okay... someone in England just got notified of my order. I went through the coding yesterday on the wiki as well as the blog. I thought I saw a set up for a Cartesian printer (example config) but now I can't find it.

RepRapFirmware configuration guides:

Cartesian, and base for the others: [reprap.org]
Delta: [reprap.org]
CoreXY, CoreXZ etc.: [reprap.org]


Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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