CNC newbie - Machinekit from scratch

[Richard Thornton]

Hi,

Apologies if this has been asked before.

My computer knowledge is great, electronics knowledge is average and my CAM knowledge is poor.

I have a CNC6040 (for around 5 years it has been gathering dust and spider-webs in the shed) it has the VFD and the water-cooled spindle.

Back in the day the first thing I did with the 6040 is replace the drivers with a G540.

I had LinuxCNC running on an old PC with a parallel port, I could move the steppers, I never actually routed anything.

Fast forward to today and I want to get this thing running properly but so much has changed.

I just ordered a Terasic Atlas-SoC from Mouser and it should arrive today (Initially I actually didn't realise there was a version without the ARM SoC and I ordered a DE0-Nano from Adafruit, not really cost effective for me to return it from AU to US).  I also have a BBB with a Necitec Panther cape.

Should I use the Terasic, also I see the DE0-Nano_DB25, do I need that with the G540, if I do, is it possible to have the board made up with the components installed (I was thinking of using jumper wires from the Terasic directly to a DB25)?

Is my understanding correct, I install machinekit on the Terasic, it's headless, so I install something else on to a PC with a GUI and use this to send the gcode to the Terasic?

I'm thinking I would want a pendant attached to the Terasic, I don't want to spend more that $100 on this, is there something I can get online that will work on machinekit?

How do I handle the spindle/VFD (HY01D523B) and pump in machinekit? 

I probably want to add a touch off late and/or limit switches how to do that in machinekit?

From my notes the G540 has the extra capacity to handle the above:

IEC power outlet for one relay output for the spindle pump. 

2-pole socket for the other relay output. This would just be the switched relay contacts (Unpowered). You could use this for switching the FWD contacts of the VFD etc.

Four G540 inputs bought out to a DB-9 socket. Would could then wire these to limit switches etc.

Three G540 VFD outputs would be bought out to a DB9 plug.  You could use this to control the speed of your VFD.

2nd parallel port cable connector for expansion at a later date.

Sorry about all the questions.

Thanks.

Richard

[Richard Thornton]

Thanks Chris, not sure where that PC is, the PC basically could jog
the steppers with the keyboard and that was it, I hadn't tried to
integrate anything else, from my email history I can see that when I
sent what I thought was good gcode, I just got loads of:

Program exceeds machine minimum on axis x
Program exceeds machine minimum on axis y
Program exceeds machine minimum on axis z
Linear move on line 7 would exceed joint 0's negative limit

So I still had a way to go, my lack of CNC knowledge was a bit of a
brick wall for me.

I would have no problems getting machinekit running, it's which pins
on the Terasic I need to connect to the pins on the G540 and whether I
actually need DE0-Nano_DB25, it seems to have switching circuitry to
mimic more DB25 ports, like a mesa board I guess, I probably need
DE0-Nano_DB25 (I don't personally have surface mount soldering skills)
to give me more I/O for the VFD/relays/touch off plate/limit switches?

Newbie alert!

On 19 February 2018 at 12:24, Chris Albertson <alberts...@gmail.com> wrote:
> Does the old PC still work and can it still move the steppers? If so you
> have a good start. Then you change ONE thing at a time.

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> Chris Albertson
> Redondo Beach, California

[Richard Thornton]

Actually I found a post from Charles Steinkuehler saying that it isn't a 74CBTLV3861 it's a SN74CBTD3861DW which seems to add level shifting, I think the G540 is tolerant of 3.3 or 5v?

>> email to machinekit+unsubscribe@googlegroups.com.

[Richard Thornton]

Also is it possible to add an LCD to the Terasic to show the XYZ coordinates?

Thanks!

[Charles Steinkuehler]

On 2/18/2018 6:11 PM, Richard Thornton wrote:
>
> Should I use the Terasic, also I see the DE0-Nano_DB25, do I need that with
> the G540, if I do, is it possible to have the board made up with the
> components installed (I was thinking of using jumper wires from the Terasic
> directly to a DB25)?

That can work if you don't have any signals over 3.3V. The
DE0-Nano_DB25 adapter board has FET based bus translation chips that
protect the FPGA from 5V signals.

In addition to the 5V protection, you may want or need additional
protection on the I/O signals. In a typical setup using Mesa
hardware, you have an FPGA board (with built-in 5V protection)
connected to an I/O board that provides isolation and additional
drive, for example a 5i25 FPGA card and 7i76 daughtercard.

The DE0-Nano + the DE0-Nano_DB25 adapter board would be the same as
the 5i25. Whether or not you need something like the 7i76 depends on
your system, but it's generally not a great idea to connect pins
directly tied to the FPGA to long cables winding around a large
machine with lots of EMI. You can probably get away with tying the
stepper signals directly to the FPGA board but things like limit
switches and encoder signals can easily pick up enough EMI to fry the
FPGA if you're not careful.

> Is my understanding correct, I install machinekit on the Terasic, it's
> headless, so I install something else on to a PC with a GUI and use this to
> send the gcode to the Terasic?

Yes.

> I'm thinking I would want a pendant attached to the Terasic, I don't want
> to spend more that $100 on this, is there something I can get online that
> will work on machinekit?

There are a variety of pendents available, and quite a few of them
already have HAL components to use them.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Charles Steinkuehler]

On 2/18/2018 8:33 PM, Richard Thornton wrote:
> Actually I found a post from Charles Steinkuehler saying that it isn't a
> 74CBTLV3861 it's a SN74CBTD3861DW which seems to add level shifting, I
> think the G540 is tolerant of 3.3 or 5v?

The chips serve to limit the voltage seen by the FPGA on input
signals. Basically, any signal from 0.0V to 3.3V passes through
unchanged, while signals above 3.3V will be 'clipped' to 3.3V.

So that works well for inputs from things like 5V encoder or limit
switch signals, but any outputs from the FPGA will still only be 3.3V.

Whether the 3.3V is enough to drive your motor controllers will depend
on the specific model, but most are setup for a 5V-12V input signal
driving the LED in the optoisolator.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Richard Thornton]

Thanks Charles.

Is anyone on the list producing complete DE0-Nano_DB25's for sale?

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[Charles Steinkuehler]

On 2/20/2018 4:40 AM, Richard Thornton wrote:
> Thanks Charles.
>
> Is anyone on the list producing complete DE0-Nano_DB25's for sale?

Not that I know of, sorry.

The boards are available from OSH-Park:

https://oshpark.com/shared_projects/ZSjsiCUd

...and they're pretty easy to assemble, just make sure you use the
real part numbers in the BOM rather than the generic KiCAD library
part name shown on the schematic:

https://github.com/cdsteinkuehler/bobc_hardware/blob/CRAMPS/DE0-Nano_DB25/DE0-Nano_DB25.ods?raw=true

Of course the main reason to have one of the DE0-Nano_DB25 boards is
for talking to Mesa hardware. If you're not wanting to use Mesa DB25
daughter boards, you may want to just wire up something custom (since
you will probably need more driver and protection logic than is on the
DE0-Nano_DB25 anyway). The DE0 uses standard 0.025" pin headers on
0.1" spacing so you can mount matching sockets on perfboard or use a
(short!) ribbon cable to connect to a hand wired breakout/driver board.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Richard Thornton]

Thanks Charles.

I'm confused.

I thought the machinekit firmware for the de0-nano programmed the fpga for motion control to provide a very high quality pulse train to the drivers?

Bearing in mind my previous posts in this thread is there something I can buy to properly interface a de0-nano to a g540 that's connected to a 6040, could I use the beaglebone cape I have with jumper wires, is it only really isolation and 3.3v/5v logic shifting that I want between the de0-nano and the g540?

Thanks again.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Charles Steinkuehler]

On 2/20/2018 1:55 PM, Richard Thornton wrote:
> Thanks Charles.
>

> I'm confused.
>
> I thought the machinekit firmware for the de0-nano programmed the fpga for
> motion control to provide a very high quality pulse train to the drivers?

Yes.

> Bearing in mind my previous posts in this thread is there something I can
> buy to properly interface a de0-nano to a g540 that's connected to a 6040,
> could I use the beaglebone cape I have with jumper wires, is it only really
> isolation and 3.3v/5v logic shifting that I want between the de0-nano and
> the g540?

The Gecko 540 manual says it's OK with a 3.3V input signal and it
looks like it also provides for four input signals. I'm not sure how
protected those input are, but if the signals on the DB25 can be
configured to not go over 3.3V, the G540 may be all you need.

...and assuming the G540 is mounted in close proximity to the
DE0-Nano, you likely don't need anything fancy in the way of buffers
or translation logic.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Richard Thornton]

Thanks Charles, much appreciated.

Sorry for the newbie questions.

With machinekit on the de0-nano is there a pinout to stepper drivers?

Say I get machinekit on the de0-nano running and correctly cabled, do I just install machinekit on an x86_64 pc, load my drawing and send it to the de0-nano over IP, are there instructions for all of this?

Thanks again.

[Charles Steinkuehler]

On 2/20/2018 2:25 PM, Richard Thornton wrote:
> Thanks Charles, much appreciated.
>
> Sorry for the newbie questions.
>
> With machinekit on the de0-nano is there a pinout to stepper drivers?

Yes, but since it's an FPGA it can be pretty much whatever you want in
terms of how many stepgens, encoders, etc. There are some existing
configs which may or may not work for you, see the PIN_* files:

https://github.com/machinekit/mksocfpga/tree/master/HW/hm2/config/DE0_Nano_SoC_DB25

...depending on what you need for I/O pins. I notice there is a
conspicuous lack of a configuration for something like a G540 (or even
stepgen + GPIO on the same DE0-Nano pin-header). I can make one if
you'd like.

> Say I get machinekit on the de0-nano running and correctly cabled, do I
> just install machinekit on an x86_64 pc, load my drawing and send it to the
> de0-nano over IP, are there instructions for all of this?

You only need Machinekit installed on the DE0-Nano. For an interface,
you either need to use X11 forwarding and bring up the display on a
different machine (the Axis GUI or one of the other traditional
LinuxCNC GUIs), or you can use one of Alexander's Qt interfaces (Cetus
or Machineface) which are designed to run on a tablet or remote computer.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Richard Thornton]

Thanks again Charles.

Could you please create a G540 configuration for a DE0-Nano?

On 21 February 2018 at 09:01, Charles Steinkuehler

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[Charles Steinkuehler]

On 2/20/2018 11:39 PM, Richard Thornton wrote:
> Thanks again Charles.
>
> Could you please create a G540 configuration for a DE0-Nano?

I'll try to get to this in the next day or two. I'll use the same
DB25 pinout as the other configurations, so if you want to you can get
one of the DE0-Nano_DB25 boards from OSH-Park, or you can just wire it
up by hand.

Is there anything in particular you'd like on the second DB25 other
than GPIO pins?

--
Charles Steinkuehler
cha...@steinkuehler.net

[Richard Thornton]

Thanks Charles.

Am I right in thinking that the second DB25 would be for connecting:

1/ LCD (character type for XYZ axis positions)
2/ Limit-switches
3/ MPG pendant
4/ Touch-Off-Plate

To the group please let me know if there are specific recommendations
on the above that play nice with the DE0_Nano and Machinekit, for
instance:

1/ https://www.adafruit.com/product/198 (20x4 HD44780 LCD)
2/ https://www.adafruit.com/product/818 (switch with lever)
3/ https://cnc4pc.com/catalog/product/view/id/38/s/mpg2-pendant/category/157/
(MPG2)
4/ https://www.ebay.com/itm/291774184069?ViewItem=&item=291774184069 (T-O-P)

Thanks.

Richard


On 21 February 2018 at 23:37, Charles Steinkuehler

[Richard Thornton]

This looks pretty cool , will this work with the DE0_Nano or does it
need to go through the DE0-Nano_DB25:

http://store.mesanet.com/index.php?route=product/product&product_id=116


On 22 February 2018 at 12:47, Richard Thornton

[Charles Steinkuehler]

On 2/21/2018 9:09 PM, Richard Thornton wrote:
> This looks pretty cool , will this work with the DE0_Nano or does it
> need to go through the DE0-Nano_DB25:
>
> http://store.mesanet.com/index.php?route=product/product&product_id=116

That should work with anything that has an RS-422 serial interface,
but I don't know what drivers are available for Machinekit/LinuxCNC to
talk to it.

Note you can turn most any serial UART interface into an RS-422
interface with an appropriate driver chip.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Charles Steinkuehler]

I believe there are HAL drivers that will talk to LCD modules like the
HD44780 and similar.

AFAIK, you can use any of the I/O pins for things like limit switches
if you disable the "special function" I/O (ie: stepgen, encoder, etc).

The I/O for an MPG pendant is specific to the pendent you choose, some
are USB, some need discrete I/O. I haven't worked much with these so
I'm not real familiar with the options.

I think a touch-off plate should just require a single GPIO input pin.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Charles Steinkuehler]

On 2/21/2018 6:37 AM, Charles Steinkuehler wrote:
> On 2/20/2018 11:39 PM, Richard Thornton wrote:
>> Thanks again Charles.
>>
>> Could you please create a G540 configuration for a DE0-Nano?
>
> I'll try to get to this in the next day or two. I'll use the same
> DB25 pinout as the other configurations, so if you want to you can get
> one of the DE0-Nano_DB25 boards from OSH-Park, or you can just wire it
> up by hand.
>
> Is there anything in particular you'd like on the second DB25 other
> than GPIO pins?

Added:
https://github.com/machinekit/mksocfpga/commit/7e81953c7a7971daaa08c533ef1cc828dbd9fcdd

I copied the Mesa G540 configuration for the 5i25. This includes
support for an encoder on the input pins, but you also use the pins as
GPIO for limit switches. The second DB25 is another instance of the
G540, so you can have up to 8 steppers and 2 encoders.

Let me know if you run into any problems.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Richard Thornton]

Thanks Charles,

Just looking at the commit.

The meat of it is lines 113-192.

So you have created two DB25's with just GPIO_0?

GPIO_1 is unused, or its pure GPIO (this is what disabled the "special
function" I/O looks like)?

Line 112, 133, 154 shows DB25-P2, three P2?
Line 175 shows DB25-P3

Line 115, 118, 119, 122, 124 are StepGenStepPin, five of those?
Line 117, 121, 123, 125 are StepGenDirPin

With this config which pins would I use for GPIO, GPIO_1 (LCD, relay,
VFD, pendant, limits, T.O.P)?

Line 114 is PWMAOutPin, what is that to connect to Pulse Width
Modulation right, maybe for a VFD for the spindle?

Because I only need four steppers and one encoder should I just make
lines 134-150 the same as lines 155-171?

Would you know of a reference guide that shows the format, syntax and
what the special function are in these vhd files?

Thanks again, I'm learning a lot!

On 23 February 2018 at 01:50, Charles Steinkuehler

[Charles Steinkuehler]

On 2/22/2018 9:41 PM, Richard Thornton wrote:
> Thanks Charles,
>
> Just looking at the commit.
>
> The meat of it is lines 113-192.
>
> So you have created two DB25's with just GPIO_0?

There are two DB25's connected to the DE0-Nano's GIPO_0 header, both
of which will support a G540. This part is basically a copy of the
Mesa G540 configuration for th 5i25.

There are two more DB25's with just I/O pins connected to the
DE0-Nano's GPIO_1 header.

You should probably use the first set of DB25 pins on GPIO_0:

https://github.com/machinekit/mksocfpga/blob/master/HW/hm2/config/DE0_Nano_SoC_DB25/PIN_G540_G540_GPIO_GPIO.vhd#L113-L129

> GPIO_1 is unused, or its pure GPIO (this is what disabled the "special
> function" I/O looks like)?

Yes, GPIO_1 is just plain I/O pins in hostmot2, no special functions.

> Line 112, 133, 154 shows DB25-P2, three P2?
> Line 175 shows DB25-P3

Line 133 should be P3. P2 and P3 are the DB25 headers on the
DE0-Nano_DB25 breakout board.

> Line 115, 118, 119, 122, 124 are StepGenStepPin, five of those?
> Line 117, 121, 123, 125 are StepGenDirPin

Yes, I just copied the Mesa setup. You don't have to use the pins as
stepper driver outputs, they can be used as GPIO instead.

> With this config which pins would I use for GPIO, GPIO_1 (LCD, relay,
> VFD, pendant, limits, T.O.P)?

Whichever pins you need. Any pin can be an I/O pin.

> Line 114 is PWMAOutPin, what is that to connect to Pulse Width
> Modulation right, maybe for a VFD for the spindle?

Yes.

> Because I only need four steppers and one encoder should I just make
> lines 134-150 the same as lines 155-171?

You shouldn't have to make any changes to the VHDL file or FPGA bit
file, just setup the hostmot2 driver properly in HAL.

> Would you know of a reference guide that shows the format, syntax and
> what the special function are in these vhd files?

There's no real documentation other than the VHDL source. I asked
Peter if he has a utility for creating the PIN files since there are
so many of them and he just creates them by hand.

--
Charles Steinkuehler
cha...@steinkuehler.net

[Charles Steinkuehler]

On 2/23/2018 7:29 AM, Charles Steinkuehler wrote:
> On 2/22/2018 9:41 PM, Richard Thornton wrote:
>
>> With this config which pins would I use for GPIO, GPIO_1 (LCD, relay,
>> VFD, pendant, limits, T.O.P)?
>
> Whichever pins you need. Any pin can be an I/O pin.

Just a warning that the pin numbering can be a bit confusing if you're
not using one of my breakout boards (and just going by the DB25 pin
numbers listed in the PIN_ file). You have to follow a fairly long
chain to figure out exactly what hm2 pin is connected to a particular
physical pin:

* Everything starts with the PIN_* file which specifies what functions
are mapped to which pins. The pins are listed in "hostmot2" order,
lowest to highest (the hostmot2 instance exports an array of pins to
the top-level

https://github.com/machinekit/mksocfpga/blob/master/HW/hm2/config/DE0_Nano_SoC_DB25/PIN_G540_G540_GPIO_GPIO.vhd#L111-L130

* The iobits signals get mapped to specific GPIO_0 and GPIO_1 signals
in the top-level VHD file to make routing to the DB25 connector easy:

https://github.com/machinekit/mksocfpga/blob/master/HW/hm2/config/DE0_Nano_SoC_DB25/PIN_G540_G540_GPIO_GPIO.vhd#L113-L129

* You then need to look up the physical header pin that particular
GPIO signals is routed to on the DE0-Nano (via the schematic or the
reference manual):

http://www.terasic.com.tw/attachment/archive/941/DE0-Nano-SoC_User_manual_rev.C1.pdf

* Then you need to follow that signal from the pin header to the DB25
connector on the DE0-Nano_DB25 break-out board:

https://github.com/cdsteinkuehler/bobc_hardware/blob/CRAMPS/DE0-Nano_DB25/DE0-Nano_DB25.pdf


So, for example:

* hostmot2 I/O signal 0 is specified as a GPIO pin in the PIN_ file
(it has no secondary function defined).

* iobits(0) is mapped to GPIO_0(16) in DE0_Nano_SoC_DB25.vhd

* GPIIO_0(16) is on pin 19 of the pin header per the user manual

* P1 pin 19 on the breakout board connects to J1B0 which becomes J1-0
(after the bus translator) and is connected to P2 pin 1

Easy-Peasy! ;-)

--
Charles Steinkuehler
cha...@steinkuehler.net

[Richard Thornton]

Thanks Charles!

OK so I'm looking at this again, so to cable the DE0 to the G540 for X
AXIS stepper control:

x step is I/O 02 which is GPIO_0[14] or pin 17 J1B2 J1-2 pin 2
x dir is I/O 04 which is GPIO_0[12] or pin 15 J1B4 J1-4 pin 3

So I connect pin 2+3 on the DE0 to pin 2+3 on the G540 DB25?

Assuming that's correct, is it easy enough for me to just go in to
machinekit and jog the X stepper?

On 24 February 2018 at 00:53, Charles Steinkuehler

[Richard Thornton]

I'm really confused...why do I have to go through the DE0-Nano_DB25
schematic, if I'm not using the DE0-Nano_DB25?

x step is I/O 02 which is GPIO_0[14] or (GPIO_0 physical) pin 17
x dir is I/O 04 which is GPIO_0[12] or (GPIO_0 physical) pin 15
y step is I/O 06 which is GPIO_0[10] or (GPIO_0 physical) pin 13
y dir is I/O 08 which is GPIO_0[08] or (GPIO_0 physical) pin 9
z step is I/O 09 which is GPIO_0[09] or (GPIO_0 physical) pin 10
z dir is I/O 10 which is GPIO_0[06] or (GPIO_0 physical) pin 7

So:

DE0 GPIO_0 pin >> G540 DB25
17 >> 2
15 >> 3
13 >> 4
9 >> 5
10 >> 6
7 >> 7