BBB RootCape - New Cape for BBB
Peter RCNC Newbery
Hey everyone,
I thought I might share a post about this project I have been working on.
A little background: I'm the designer for the Root CNC project also known as Sailorpete on Thingiverse and the forums (although I’m typically quite on them). I currently building the next revision of the project - Root 4 and I wanted a real time motion controller that I could grow into whilst not breaking the bank. I currently use an Arduino controller running a modified version of Marlin, it been working well for the past couple of years but this isn’t real time and doesn’t have some of the features I’m after, like RS 458 comms. I’m an Electronic engineer by trade and the hardware side of the project I understand; the software side is a little difficult so I might be asking more questions down the road.
Currently Root CNC uses some low current Nema23 that have been work great for 3+ years without any issues. These steppers are been driven by the small DRV8825 stepper motor drivers and I’ve never lost any steps nor had any issues. I’m planning on using the same drivers for the new CNC but because this machine is much bigger than the last, I wanted to prevision the breakout the control signals to connector and allow me to use a standard stepper motor driver; Either a PNP or NPN connection type whilst disabling the onboard drivers.
I’m new the whole LinuxCNC/ Machinekit setup and I’ve only had a BBB setup on my desk with a single motor connected to it. I’ve found it partially hard to prototype anything with the BBB due to the lack of available capes for sale. So cost is one of my main driving factors for this cape as its very much a prototype for me. My main reason for Machinekit is seeing this software running on the PocketCNC – so I know it can handle my 3 or 4 Axis machines.
So this is what I have come up with:
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.png?part=0.3&view=1)
I’m planning on getting these boards assembled by JLCPCB.
Features
- 4x Analogue inputs (temperature monitoring)
- EEPROM for Cape configuration
- Isolated RS-485 Communication (Spindle ETC)
- Emergency Stop switch (by passable)
- Buffered I/O (5V tolerant)
- 8x Open collector or standard switch digital inputs for endstop
- Supports inductive probes with selectable supply voltage
- Discrete spindle control (spindle ON, Dir, PWM)
- 4x Power outputs (Mist, Dust extractor, coolant etc)
- 6x stepper motor drivers (DRV2285)
- 6x stepper motor control signal (By pass onboard drivers)
I thought you’ll be interested in this and I thought it’ll be a good opportunity to see what others thought about it before I order a prototype.
Kind Regards Pete (Sailorpete)
John Dammeyer
Hi Peter,
Much of what you are providing is already there with the Replicape which by the looks of it is out of stock.
https://www.thing-printer.com/product/replicape/
I've got one but haven't yet connected it to my Delta 3D printer. I had problems with the Manga Screen touch sensitivity. I sent it back and it was confirmed to be working. Came back here and didn't work any better. I then bought a Manga 2 screen but haven't progressed with the project.
Looking at the Root CNC web site it seems like you have a pretty impressive little project there. And I believe the BBB software to support such a printer is already in place with the replicape. So I'd suggest from a software perspective that is a good starting point. Granted it's targeted at 3D printing but the infrastructure for motor control is there.
I have a CNC router running with MACH3 and more than happy with it. Haven't seen a reason to change over to anything else that has 3A 55V drivers. And a CNC router is definitely a project that requires a CNC program. It's not something you use with hand wheels like a milling machine.
OTOH, a milling machine that comes as manual with handles will generally also require larger stepper motors and drives right away. So drivers on the board are a waste so I'm not sure users would jump in that direction.
John
--
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Peter RCNC Newbery
Hi John,
I am aware of the Replicape hardware but they’re no longer producing this cape and its being phased out for their new up and coming hardware, so again there is little to no cape support available for the BBB. I starting to think the BBB might not be the best solution…
What are other people using?
However, I don’t think I was clear with my first post. I’m not building this for a 3D printer. This it for a CNC router.
I might hold of a little longer with this cape and re-access my options. I might stay with Marlin (known and working solution for me but not real time) or look more into some other options on the market that don’t break the bank.
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Jason Kridner
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John Dammeyer
Hi Jason,
I think you've pointed out something interesting here. The fundamental center of pretty well any CNC system isn't the processor or the motors. It's in fact the Break Out Board!
The question then becomes what goes on the Break Out Board and how much does it do.
My box of unused break out boards, accumulated about 14 years ago consists of:
https://www.probotix.com/CNC-CONTROL-SYSTEMS/BREAKOUT-BOARDS/PBX-RF
This now goes for
BTW, Probotix makes a cape for the BBB which I don't have.
https://www.probotix.com/CNC-CONTROL-SYSTEMS/BREAKOUT-BOARDS/PBX-BB
but also states they don't offer support. At $159.95 it's pretty expensive I think but does allow LCD capes like the LCD4 (which I also have). Note it's also not so much as a BoB as an interface to the rest of the products that they sell.
I've also got an Ohmikron PPT1006 (discontinued) Here's a link to a posting and a photo
https://buildbotics.com/archive/cad_cam_edm_dro/messages/91260
Like the Probotix designed for their own stepper boards with minimal screw terminals.
Finally a small board with a male DB-25 and screw terminals along with some opto isolators.
Other than the Ohmikron setup which runs my ELS controlled Gingery Lathe the others never made it into a CNC project. I did use the Xylotex Cape I have to run to the Probotix BoB to do MachineKit testing with the BBB on my mill.
But ultimately I've ended up with the newer PMDX-126 on the mill and still have the older PMDX-125 on the CNC router run with MACH3 and a PC. But this PC talks to the hardware with a USB Smooth Stepper (ribbon cables) while the mill is either parallel port or MESA 7i92H (Ethernet) into the PMDX-126 DB-25.
The PMDX-125/126 are tailored for the Smooth Steppers with registered mounting holes and the ribbon cable sockets positioned for easy access to the Smooth Stepper. There's an FPGA on the BoB that deals with charge pump input, fault and errors and the BoB has a transformer for a power supply and a couple of relays.
So you plop the BoB in the middle of the cabinet, add perhaps a DIN rail for some relays and extra screw terminals. Mount the external motor drives and power supplies and run the wires. True it's $174 w/o cables.
I question the need for the MESA 7i92H or the Smooth Stepper when instead of either of those at a much lower price you could plug in a BeagleBone.
If I was going to design something I think I'd marry the concept of the LCD support that is provided by the Probotix PBX-BB along with the PMDX-126 but let's call it a PMDX-BB.
Then it becomes a choice of a system with LCD display, touch screen and a Pendant on a pedestal. Or a system with Pendant, HDMI screen and keyboard/mouse with the electronics buried inside the control box.
No one BoB is going to be able to address all types of machines. But I'd build on the success of the PMDX-125/126 systems. Especially their FAULT and ERROR and ESTOP handling along with their expansion for things like PWM to 0-10V for Spindle speed control.
And instead of an FPGA on the BoB, I'd look at CAN bus and CANopen as a connection to specialty hardware and the outside world.
Anyway. Even if the PC is free the WIN-10 OS and either MACH c/w Smooth Stepper is not. Or if the PC is free, as is LinuxCNC, the MESA interface (which it appears most use for LinuxCNC) is not. And the Break Out Board in some form is still required. Whether it be from MESA or something like the PMDX-126.
The BBB with the two co-processors can create a reasonable 5 axis CNC system with spindle speed control and feedback for power tapping. Add CAN bus (don't use the CAN pins for I/O) expansion for the slower I/O like coolant, tool changers, automatic clamps etc. you have the basics of an industrial controller for pick and place or CNC or 3D printing.
IMHO
John Dammeyer
To view this discussion on the web visit https://groups.google.com/d/msgid/machinekit/CA%2BT6QP%3D3gNEMW9hnTb91RodRsRQrsU0WCM-NO6gfe7k9s4_6dQ%40mail.gmail.com.
Len Shelton
Well said, John.
We also have a board that we use, but don't sell separately that sits
on top of our PBX-BB with two parallel port connectors on it. So right
now we are still using a PC with two parallel ports or a 6i25. Our hope
is that the BB will one day drop on top of that to replace the PC. We
are hopeful that the BB-AI will be powerful enough to do what we want,
but haven't had time to test it yet. Our ultimate goal is to have an
internet connected, but standalone with its own touchscreen LCD
controller, 6 joint/5 axis CNC controller with enough I/O to do LCD,
homing, MPG pendant, and a few other for probes, coolant, etc - for
light indutrial use.
>Len
ce...@tuta.io
May 14, 2020, 15:46 by jkri...@beagleboard.org:
> All of this is why I'd started a thread about making a Machinekit-focused cape with Seeed. Also, I'd want to bake-in support for the BeagleBone AI, which should give people a big boost in UI performance.
>
> I started making a feature priority list, but then got distracted: > https://github.com/beagleboard/capes/wiki/Motion-Control-Cape
>
> What you've put together looks pretty nice. The drivers vs. no-drivers on-board debate is an interesting one. You can source these things on their own a whole lot cheaper than you can get the break-out boards. And putting break-out boards in your designs add a lot of cost and space. Maybe the space isn't so much a concern. The biggest concern in my mind is having more points of failure. How do we make something "just work" for those trying to get into this space for the first time?
>
> I certainly don't have the answers. If you/we can make something that works for an interesting and engaged set of the Machinekit population, that'd be good with me. Ultimately, what I want to make is a pick-and-place machine for myself so that I can bootstrap Beagles making Beagles. Still, I'd be happy as a first step if I can just replace the 3D printer controllers with something Beagle-based that I can understand and hack.
>
> I should check in with the PocketNC folks to see what their cape requirements are. I'm sure I've checked in the past, but I slept since then.
>
Cern.
>
> On Sun, Apr 5, 2020 at 4:11 PM Peter RCNC Newbery <> rcn...@gmail.com> > wrote:
>
>>
>> Hi John,
>>
>>
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>> What are other people using?
>>
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>> I might hold of a little longer with this cape and re-accessmy options. I might stay with Marlin (known and working solution for me but notreal time) or look more into some other options on the market that don’t breakthe bank.
>>
>>
>>
>>
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>> On Saturday, April 4, 2020 at 11:58:55 PM UTC+1, John Dammeyer wrote:
>>
>>>
>>> Hi Peter,
>>>
>>>
>>> Much of what you are providing is already there with the >>> Replicape>>> which by the looks of it is out of stock.
>>>
>>>
>>> https://www.thing-printer.com/product/replicape/
>>>
>>>
>>> I've got one but haven't yet connected it to my Delta 3D printer.>>> >>> I had problems with the Manga Screen touch sensitivity.>>> >>> I sent it back and it was confirmed to be working.>>> >>> Came back here and didn't work any better.>>> >>> I then bought a Manga 2 screen but haven't progressed with the project.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> I have a CNC router running with MACH3 and more than happy with it. >>> >>> Haven't seen a reason to change over to anything else that has 3A 55V drivers.>>> >>> And a CNC router is definitely a project that requires a CNC program.>>> >>> It's not something you use with hand wheels like a milling machine.
>>>
>>>
>>>
>>>
>>>
>>> OTOH, a milling machine that comes as manual with handles will generally also require larger stepper motors and drives right away.>>> >>> So drivers on the board are a waste so I'm not sure users would jump in that direction.
>>>
>>>
>>>
>>>
>>>
>>> John
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> From:>>> >>> machi...@googlegroups.com <>>>> [mailto:>>> machi...@googlegroups.com <>>>> ] >>> On Behalf Of >>> Peter RCNC Newbery
>>> Sent:>>> April-04-20 3:03 PM
>>> To:>>> Machinekit
>>> Subject:>>> [Machinekit] BBB RootCape - New Cape for BBB
>>>
>>>
>>>
>>>
>>> Hey everyone,
>>>
>>>
>>>
>>>
>>>
>>> I thought I might share a post about this project I have been working on.
>>>
>>>
>>>
>>>
>>>
>>> A little background: I'm the designer for the Root CNC project also known as Sailorpete on Thingiverse and the forums (although I’m typically quite on them). I currently building the next revision of the project - Root 4 and I wanted a real time motion controller that I could grow into whilst not breaking the bank. I currently use an Arduino controller running a modified version of Marlin, it been working well for the past couple of years but this isn’t real time and doesn’t have some of the features I’m after, like RS 458 comms. I’m an Electronic engineer by trade and the hardware side of the project I understand; the software side is a little difficult so I might be asking more questions down the road.
>>>
>>>
>>>
>>>
>>>
>>> Currently Root CNC uses some low current Nema23 that have been work great for 3+ years without any issues. These steppers are been driven by the small DRV8825 stepper motor drivers and I’ve never lost any steps nor had any issues. I’m planning on using the same drivers for the new CNC but because this machine is much bigger than the last, I wanted to prevision the breakout the control signals to connector and allow me to use a standard stepper motor driver; Either a PNP or NPN connection type whilst disabling the onboard drivers.
>>>
>>>
>>>
>>>
>>>
>>> I’m new the whole LinuxCNC/ Machinekit setup and I’ve only had a BBB setup on my desk with a single motor connected to it. I’ve found it partially hard to prototype anything with the BBB due to the lack of available capes for sale. So cost is one of my main driving factors for this cape as its very much a prototype for me. My main reason for Machinekit is seeing this software running on the PocketCNC – so I know it can handle my 3 or 4 Axis machines.
>>>
>>>
>>>
>>>
>>>
>>> So this is what I have come up with:
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>>> Features
>>>
>>> 4x Analogue inputs (temperature monitoring)
>>> EEPROM for Cape configuration
>>> Isolated RS-485 Communication (Spindle ETC)
>>> Emergency Stop switch (by passable)
>>> Buffered I/O (5V tolerant)
>>> 8x Open collector or standard switch digital inputs for endstop
>>> Supports inductive probes with selectable supply voltage
>>> Discrete spindle control (spindle ON, Dir, PWM)
>>> 4x Power outputs (Mist, Dust extractor, coolant etc)
>>> 6x stepper motor drivers (DRV2285)
>>> 6x stepper motor control signal (By pass onboard drivers)
>>>
>>>
>>>
>>>
>>> I thought you’ll be interested in this and I thought it’ll be a good opportunity to see what others thought about it before I order a prototype.
>>>
>>>
>>>
>>>
>>>
>>> Kind Regards Pete (Sailorpete)
>>>
>>>
>>>
>>> --
>>> website: >>> http://www.machinekit.io>>> blog: >>> http://blog.machinekit.io>>> github: >>> https://github.com/machinekit
>>> ---
>>> You received this message because you are subscribed to the Google Groups "Machinekit" group.
>>> To unsubscribe from this group and stop receiving emails from it, send an email to >>> machi...@googlegroups.com <>>>> .
>>>
>>>
>>
>>
>>
>> --
>> website: >> http://www.machinekit.io>> blog: >> http://blog.machinekit.io>> github: >> https://github.com/machinekit
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>> To view this discussion on the web visit >> https://groups.google.com/d/msgid/machinekit/b7a014dc-ebbe-4247-81b1-9d76d3f261ca%40googlegroups.com <https://groups.google.com/d/msgid/machinekit/b7a014dc-ebbe-4247-81b1-9d76d3f261ca%40googlegroups.com?utm_medium=email&utm_source=footer>>> .
>
>
> --
> https://beagleboard.org/about> - a 501c3 non-profit educating around open hardware computing
>
>
>
> website: > http://www.machinekit.io> blog: > http://blog.machinekit.io> github: > https://github.com/machinekit
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>