[Noisebridge-discuss] getting that goddamned mill to work

Mon Oct 5 07:06:38 UTC 2009

Hi Jon,

That's awesome.  I now have a HAL file which produces a quadrature  
output on 2 pins (1-0,1-1,0-1,0-0) using halmeter and EMC2 as a  
simulator.

To be able to watch the steps I had to give it a special 0.0001" jog  
setting, since all the others happened to be full phase cycles (and so  
ended up with the same line hi).

I started with Seph's OL config, so all the pins will need to change  
and I'll need to put in a spindle control.  Basically we have 2 HAL  
files, one that's from stepper-conf that has all the right pins, 4th  
axis, and working spindle pwm, and a second one based on the one from  
Seph that should be able to exercise the stepper motor driver properly.

mike

On Oct 4, 2009, at 7:37 PM, Jonathan Foote wrote:

> Latest on the MaxNC mill. Today I verified that quadrature signals
> work, by the simple expedient of hooking up a quadrature encoder:
> turning the shaft moves the axis.
>
> The entire thing needs to be disassembled, cleaned, and relubed
> because the grease is gummy and sticks.
> The Z axis is stiff, the Y axis is frozen; both pop the breaker
> sometimes.  I didn't test the X or the rotation.
>
> We also (still!) need a Linux box. Jonathan M. and I found a Thinkpad
> laptop that looked fine save it didn't have a power supply (16V at
> 4.5A if you see one). Specs are really not important as the mill
> driver board handles the critical timing.
>
> I will go ahead and build a step->quadrature converter box just
> because it would be fun. (No micros: jellybean TTL FTW! )  Need some
> 7486 XORs but couldn't find them -- do we have any? Also, if anyone
> sees a parallel port A/B box in the hack pile, that would make an
> ideal enclosure.
>
> I could use some help on the mill TLC and the linux box if people are
> keen on this!
>
>
> On Fri, Oct 2, 2009 at 12:10 PM, Michael Wright <mike at smallip.com>  
> wrote:
>> I think Jon pretty much summed it up.
>>
>> We've got it to work as well as can be done using the UI on EMC2.  It
>> looks like the EMC2 HAL (hardware abstraction layer) allows for  
>> making
>> pretty significant changes to the motor signaling (Seph basically
>> changed everything of how EMC2 talks to make it use 4 pins per motor
>> to control the MaxNC10OL), we have the MaxNC10CL (closed loop) so  
>> we'd
>> have to do slightly less work to make it do quadrature on 2 pins per
>> motor.  This would be a pure software hacking adventure, probably  
>> most
>> of the work could be done using EMC2 on a VM on a laptop, with final
>> testing requiring a real machine and the mill.
>>
>> I've downloaded and played with Mach3 demo-ware in a VM.  It actually
>> has a menu option for MaxNC CL mode.  This along with the other  
>> things
>> I've read makes me think it will work.  If it's possible to believe,
>> it actually looks more esoteric and harder to use than EMC2 (at least
>> for someone who doesn't know CAM yet).  That said if it makes the  
>> mill
>> work, someone can make an instructable on how to do CAM.  The demo of
>> Mach3 allows 500 lines of Gcode, the licensed version allows 10,000
>> and costs $175.  My plan is to arrive with a windows 2k hard drive  
>> and
>> put it in one of the three boxes (2 compaqs from Dr. J plus one from
>> Jonathan L).  If that works, then it works and other hacking can be
>> done for fun rather than "necessity".
>>
>> In terms of other hacking for fun, I'm thinking it would be pretty
>> easy to make an Arduino/Sanguino based 4 knob control box that
>> converts the perfectly good CNC mill into a functional power-feed  
>> only
>> manual mill.  For the kinds of one-off things I tend to do, having
>> direct control is nice (plus the learning curve is lower).
>>
>> The important things we learned in EMC2:
>>
>> If you have the enable pins set correctly the mill humms at about 10
>> khz (actually all 3 stepper motors)
>> If you have the enable pins set correctly any one of the steppers  
>> will
>> resist externally applied torque
>> If the steppers don't behave closed loop (hum and resist torque),
>> something's not enable and no other testing has any chance of success
>> Spindle is pin 1, inverted, it pwm's fine (if not set inverted it  
>> runs
>> by default, which I don't recommend)
>> The spindle may not be affected by the enable pins (needs more  
>> testing)
>>
>> Here's the pin config that made the most sense (and made controllable
>> noise)
>>
>> outputs:
>> 1 Spindle PWM  Invert Checked
>> 2 A Step
>> 3 A Dir
>> 4 Y Step
>> 5 Y Dir
>> 6 X Step
>> 7 X Dir
>> 8 Z Step
>> 9 Z Dir
>> 14 ESTOP Out  Invert Checked
>> 16 ESTOP Out
>> 17 ESTOP Out  Invert Checked
>>
>> Inputs
>> 10 All Limits
>> 11 Unused
>> 12 Unused
>> 13 Unused
>> 15 Unused
>>
>> On Oct 2, 2009, at 10:48 AM, Jonathan Foote wrote:
>>
>>> I don't think jitter is an issue. On the worst machine last night it
>>> was less than 25 us. Mike's borrowed machine got it down to less  
>>> than
>>> 5 (thanks for bringing that in, Mike!)
>>>
>>> Seeing as how the actual stepper pulses are generated by 4 Mhz  
>>> PICs, I
>>> think we are, if anything running too fast.
>>>
>>> But we made some progress, we got the spindle motor PWM working, and
>>> found magic enable pins. We can enable the stepper feedback so they
>>> will fight you if you try turning them out of position, and I'm  
>>> pretty
>>> sure we're giving them drive signals because we can hear them whine.
>>> But they still don't move.
>>>
>>> I think the final hurdle is generating true quadrature drive signals
>>> rather than step + direction. This is an easy hardware hack (two
>>> flip-flops and some logic should do it), or we could improve the
>>> open-source EMC2 code to generate the signals we need. The hardware
>>> solution strikes me as much easier than mucking about in the guts of
>>> that Linux port driver, but I could be convinced otherwise,  
>>> especially
>>> if there's anyone else on the planet with a similar problem. (Is
>>> anyone on the EMC2 list/forum/IRC that could ask?)
>>>
>>> I think the next step is testing that hypothesis by feeding one axis
>>> some true quadrature signals from hardware. I have some AVR code  
>>> to do
>>> just that.
>>>
>>>
>>> OK, enough hacking, back to the drama.
>>>
>>> -J
>>>
>>>
>>> On Fri, Oct 2, 2009 at 10:13 AM, Andy Isaacson <adi at hexapodia.org>
>>> wrote:
>>>> On Thu, Oct 01, 2009 at 11:56:29PM -0700, Jesse Welz wrote:
>>>>> 2009/10/1 dpc <weasel at meer.net>:
>>>>>> Michael Wright <mike at smallip.com> writes:
>>>>>>
>>>>>>> After running the Jitter-Test program on the computer I have the
>>>>>>> sinking suspicion that the machine we're trying to use isn't  
>>>>>>> good
>>>>>>> enough to send step and direction commands.
>>>>>>
>>>>>> hmmm.... i never got around to schleping down the machine for the
>>>>>> reversing stuff but just noticed it has a prallel port. how  
>>>>>> good is
>>>>>> good enough?
>>>>
>>>>
>>>> The problem is that some low-end computers from about 1998 to 2003
>>>> (and
>>>> some up to the current day) use SMI mode (System Management
>>>> Interrupt)
>>>> to do stuff on the CPU without letting the OS know about it.  This
>>>> means
>>>> that at any moment your code may stop executing for up to a few
>>>> hundred
>>>> microseconds -- plenty long enough to totally hose a PWM or stepper
>>>> motor pulse sequence.
>>>>
>>>> The motherboard I last saw being used for the mill was a Via Eden
>>>> CPU,
>>>> which is known to potentially have such issues.
>>>>
>>>> Most "real" AMD or Intel CPUs' motherboards don't have these  
>>>> issues,
>>>> although it's not guaranteed (it depends on the BIOS and system
>>>> vendor,
>>>> and laptops are also known for having such problems), so check  
>>>> for a
>>>> better mobo -- I know I saw a few in the E-Waste pile.
>>>>
>>>> -andy
>>>> _______________________________________________
>>>> Noisebridge-discuss mailing list
>>>> Noisebridge-discuss at lists.noisebridge.net
>>>> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>>>>
>>> _______________________________________________
>>> Noisebridge-discuss mailing list
>>> Noisebridge-discuss at lists.noisebridge.net
>>> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>>
>> _______________________________________________
>> Noisebridge-discuss mailing list
>> Noisebridge-discuss at lists.noisebridge.net
>> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>>