controller board recommendation?

Hello,

I am working on a design for a 3D printer. The mechanics will be a custom design but I want to use off the shelf electronics. Right now I have narrowed my choice down to the ultimaker 2 board or the RAMBo 1.3 (links below). I am looking for a recommendation on the best board to use

RAMBo
UM2 motherboard

Below are the requirements i have:

• community support, there is a great community around the reprap so i would like to use something that has a decent user base, preferably one which users are also doing custom implementations or mods.
• use a Atmega processor (at least to start with) as I am more comfortable modifying the firmware for these. I am planing to use the marlin firmware
• single board solution including the stepper drivers. I figured having the stepper drivers on a single (larger) board allows for better thermal management, using the board to dissipate the heat rather than those silly little heatsinks placed on top of each IC. If i do burn out a driver i have no concerns about resoldering a new one onto the board.
• standard features
  - 5 motors (3 axis, 2 extruder)
  - 3 endstops (6 prefered)
  - 3 heater controllers with temp feedback (2 extruders, 1 bed)
  - fan (1 minimum)
  - full graphical controller support
  - 24VDC power

I would appreciate any feedback or recommendations on which controller board to use.

Thanks

My recommendation for the main board:

A Duet 0.8.5 with 32-bit processor, 5 motors total, 5 endstops + 1 Z-probe, 2 nozzle heaters, 1 bed heater, 2 always on fans, 2 PWM fans, compatible to 24VDC, Ethernet featuring HTTP, FTP and Telnet (obviously with my web interface)

And probably rather optional, but these boards are excellent too:
dc42's PanelDue
dc42's mini IR sensor board

Edited 1 time(s). Last edit at 11/01/2015 10:26AM by zombiepantslol.

My new Duet 0.8.5 arrives tomorrow... (ordered Thursday)! I'm looking forward to it, the web interface is superior to the Smoothie firmware. It's pricey but I think it is going to be worth it.

I appreciate the recommendations. It sounds like the Duet 8.5 is highly recommended.

I do have a few questions about this board.

where is the best place to purchase it in the US?

is it possible to wire 6 endstop switches (2 for each axis)? It would be fine if the min and max are wired to the same input (so long as this does not cause a firmware issue). Basicly i am concerned that without an endstop on each end of the axis i would risk a crash if the stepper motor ever stalled or the mechanics slipped. obviously only one end would be used to home the machine but i would like the system to fault if it ever hit an endstop during operation (except homing).

Hi,

My printer was 6 endstop. These endstop are not a necessity, but is nice to have them. Already avoid several crash because of the max endstop. Still when i was configuring the firmware i have some crachs, they are not 100% crash proof. If you have an x or y crash is not big deal, the crash will not break anything. The more problematic are the crash of the Z axis, the use of an screw to move the axis allow to have more torque and can damage some hardware.

by the way, i have an radds 1.5 board; support 6 endstop, 6 motors, 2 controlled fan, 12/24v, lcd 20x4, up to 1/128 steppers. But the board is not an single board.
I have the 1/128 steppers installed, the motor do almost no noise/vibration at all.

Edited 1 time(s). Last edit at 11/02/2015 05:03AM by filipeCampos.

Like most but not all 3D printer firmwares, RepRapFirmware (the firmware that runs on the Duet) uses the endstop switches for homing only. There is no provision for having them stop the motors if they are triggered during normal moves. It would be possible to add this, but IMO it isn't necessary. In RRF you can easily adjust the stepper motor currents so that the torque is sufficient for the acceleration you want but low enough not to cause damage if you drive the head past the physical limit.

Once the printer has been homed, the range of travel is limited by software. Of course this is not perfect, because it relies on the motor not having skipped any steps since homing.

Edited 1 time(s). Last edit at 11/02/2015 05:09AM by dc42.

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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].

I don't believe there are any US sources for the Duet board. I have suggested Filastruder, which is where I bought my E3D, but so far no luck. I think you are limited to ordering from the UK right now for the 0.8.5 board.

Maybe i shouls start a new topic, but you were talking about the need of endstops and this problem is related to it so...

I have actually such a problem with my delta printer, everytime i home and do an auto bed compensation, everything works perfectly as it should. But when i leave the printer there for some minutes it suddenly loose some steps (like when you power it off) the head lowers for some millimeters and the software height is off. After that everything works as it should except the heigth of the extruder is some millimeters lower as the software expects it to be. So i can gladly crash the head in the bottom of my printer.
Anybody any idea why this happens? Voltage of the stepper drivers to low? kind of sleepfunction?

Delta
DUET 0.8.5 with latest dc42 firmware (RepRapFirmware-1.09k-dc42.bin)
42BYGHW811 NEMA-17 stepper motors

Edited 1 time(s). Last edit at 11/03/2015 06:11AM by lazy_mosquito.

Just a guess, but RepRapFirmware automatically reduces the motor currents after 30s of inactivity. With Duet-dc42 you can basically disable this feature by adding "M906 I1.0" to your config file. My fork of the firmware supports an additional "S" parameter for M84, which allows you to specify the idle timeout in seconds. M84 S0 would disable it entirely.

I have heard of the motor idle current reduction causing exactly this problem once before on a delta. So I suggest you add I0.6 to the M906 line in config.g. You should not need to go as high as I1.0. I'll add a note about this in the wiki page and change the default in the Mini Kossel config.g file.

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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].

Sorry for OT
Is it possible to put all mosfets of the A4988 to ground when the timeout comes? ( AKA shorting the coils )
This way, no current would be wasted, but the stepper-coils would be in "brake mode".
-Olaf

Brake mode would not be very effective, because the braking force is proportional to speed so the carriages would still be able to move down slowly. And the A4982s do not provide a mechanism to short the motor coils.

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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].

dc42, I've found actually that even with an m906 I parameter of 1.0, after the 30 seconds, the motors lose some current and drop about 2 thousandths of an inch (I couldn't find a metric indicator, I don't know if they even make metric dial indicators.. and I'm in Canada!) is there any way to disable the motor current idle timeout at present? I'm using your 1.09k

Quote
n8bot
I couldn't find a metric indicator, I don't know if they even make metric dial indicators.. and I'm in Canada!

Sorry for not helping with the real issue, but: [www.ebay.com]

Quote
n8bot
dc42, I've found actually that even with an m906 I parameter of 1.0, after the 30 seconds, the motors lose some current and drop about 2 thousandths of an inch (I couldn't find a metric indicator, I don't know if they even make metric dial indicators.. and I'm in Canada!) is there any way to disable the motor current idle timeout at present? I'm using your 1.09k

Strange! Do the carriages offer the same degree of resistance to movement before and after the 30 second timeout? Is the 2 thou height loss made up if you raise and then lower the head by some small amount?

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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].

Quote
n8bot
dc42, I've found actually that even with an m906 I parameter of 1.0, after the 30 seconds, the motors lose some current and drop about 2 thousandths of an inch (I couldn't find a metric indicator, I don't know if they even make metric dial indicators.. and I'm in Canada!) is there any way to disable the motor current idle timeout at present? I'm using your 1.09k

The value you need for 100% of normal motor current in idle mode is I100, not I1.0 (that would be 1%). But I suspect that I60 will be enough.

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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].