What are our current controller options?

lordmundi
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Re: What are our current controller options?

Post by lordmundi » Tue Mar 31, 2015 11:04 pm

Rarely you hear of a core feature being rejected for lack of memory.
It is very interesting that you say that. I have been talking to John Lauer recently about trying to jog with GRBL (i'm working on a jog dial and interface for the shapeoko) and how there is no way to wipe commands from the buffer. He brought up that he had heard that GRBL was simply as far as it could go and that features like a wipe couldn't be added because there was no room (I went and begged for it anyway - even offering pizza to someone who puts it into the mainline).

Anyhow, I see your point. And perhaps it wouldn't be as disruptive as I imagine. I guess I'm just excited by the possibility of GRBL and the gcode sender not having to actually stream the code constantly and deal with the tiny buffer if the file could be completely downloaded to RAM. Maybe that's not as big of a deal as I imagine. Also, having recently been told that the arduino was just not powerful enough to get something that I need, I guess I feel like if that is true, the community would need to take the next step hardware wise.

cvoinescu
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Re: What are our current controller options?

Post by cvoinescu » Tue Mar 31, 2015 11:39 pm

Ah, pizza, the universal currency in which young programmers are paid. :)

As far as I know, jogging support is in the to-do list for the next version. And I admit I've exaggerated a little about the limited memory not being a problem. It is becoming restrictive, and I'm pretty sure Sonny is planning some features that will no longer fit on the Uno.
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rtlflatt
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Re: What are our current controller options?

Post by rtlflatt » Wed Apr 01, 2015 12:03 am

lordmundi wrote: The BBB would have the advantage of having way more GPIO pins, which is always a good thing in the CNC world, and I read something somewhere saying it might be better for real-time development.
hmmm... took me a minute to realize you were talking about the Better Business Bureau. clearly i had long day at work.


and cvoinescu....
as for needing more IO pins... would something like mcp23008 or mcp23017 be of use use with uno? they add 8 and 16 io pins through the use of i2c. im not sure if that requires more memory or would disrupt regular functions of a uno running grbl tho. im gonna guess that there a reason this isnt already being done but ive been wondering for a while now.
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cvoinescu
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Re: What are our current controller options?

Post by cvoinescu » Wed Apr 01, 2015 12:19 am

I think the need for more I/O pins is more easily solved by moving to a processor with more I/O pins. The AtMega2560 has plenty of them, and GRBL already works on it.

The only minor drawback, at the moment, is that the RAMPS pinout, which is the most popular for AtMega2560-based boards, is not compatible with the current version of GRBL (because it requires the STEP and DIR pins to be on the same port). It's not a fundamental limitation, like the four-driver limit of the TinyG, but it's not just a matter of changing some settings either. I think this is why some of the GRBL "ports" are so atrocious: they haven't designed a clean, portable way to accomplish this, so they just #ifdef their way around the bits they don't like and make a mess.
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halfnormal
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Re: What are our current controller options?

Post by halfnormal » Wed Apr 01, 2015 1:23 am

cvoinescu wrote: The drivers look like ordinary TB6560 units -- they don't seem anything special. (Of course, if we had schematics, we would be able to tell for sure.)
According to their website, they are Toshiba 6600.

BTW found a wealth of information on the drivers here http://reprap.org/wiki/PiBot_TB6600_Stepper_Driver including a link to the schematic for it.
cvoinescu wrote:Also, don't get too excited by the PiBot stuff. For CNC, their controller brings only more convenient wiring compared to a bare Arduino Mega 2560 -- but it needs a custom Arduino IDE and a custom build of GRBL (yuck).
According to this page on the PiBot for Repetier Motherboard info found here, http://reprap.org/wiki/PiBot_for_Repetier_Motherboard , it links to the main Arduino site for the programming IDE. Also found this nugget on the page "All parts are licensed under CC BY-NC-SA 3.0"

cvoinescu
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Re: What are our current controller options?

Post by cvoinescu » Wed Apr 01, 2015 12:16 pm

halfnormal wrote:According to this page on the PiBot for Repetier Motherboard info found here, http://reprap.org/wiki/PiBot_for_Repetier_Motherboard , it links to the main Arduino site for the programming IDE.
For GRBL, on their site, it's definitely a modified version of the IDE. You can see it in their videos, too, it has about a dozen PiBot boards as targets.
halfnormal wrote:According to their website, they are Toshiba 6600.

BTW found a wealth of information on the drivers here http://reprap.org/wiki/PiBot_TB6600_Stepper_Driver including a link to the schematic for it.
Cool. The driver on the RepRap.org site is not the same as the one on the PiBot site. It may be a different version of the same thing, but certainly not the same (different connectors, different layout, different optocouplers). The schematic on the RepRap site is pretty much the same as every other TB6600 driver from China -- which doesn't say much about how good or bad the actual board is.
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clynad
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Re: What are our current controller options?

Post by clynad » Sun Jan 03, 2016 10:58 am

After reading this thread i noticed two options i always had in mind that were not mentioned:
(1) SOC Robotics GenY32
doest seem to be a open source option but from following there site one of there users ported grbl v8 to this board and it is mentioned as being available for download. (I am not a programer but i would gues this is a unoficial port with no support or guarantee as far as how well it was actually implemented). There was also mention of a tiny-g build for the board. In any event these guys make their own in house controller software G-Step dont know quality of it.

(2) Arduino due + Screw shield + TinyG2 + External drivers of your choice.
I dont know if its as simple as throwing all of these things togather to make a working controller

cvoinescu
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Re: What are our current controller options?

Post by cvoinescu » Mon Jan 04, 2016 1:23 am

clynad wrote:(2) Arduino due + Screw shield + TinyG2 + External drivers of your choice.
I dont know if its as simple as throwing all of these things togather to make a working controller
It should be. I haven't tried it myself, but TinyG2 is intended to work on the Due with a gShield or compatible, which means external drivers should also work. (They do with GRBL on Uno.)
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DRobs86
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Re: What are our current controller options?

Post by DRobs86 » Tue Jan 05, 2016 5:52 am

I am pretty sure that marlin has been used to run milling machines. I would like to hear the pro's and cons of using marlin and a RAMPS. Would this approach allow 4 axis milling? Is marlin's motion planner suitable for true 3d milling ?

WillAdams
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Re: What are our current controller options?

Post by WillAdams » Tue Jan 05, 2016 12:07 pm

ISTR that Marlin is based on Grbl 0.8, so doesn’t have the more advanced features (motion planner?) of 0.9.
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