Re: [Emc-users] A simple LinuxCNC system

> With the pitch of the > ballscrew at 3mm just how does one get the fine step size back . With a timing belt reduction system. Timing belts have zero-backlash and can increase torque and precision. They also can absorb tiny amounts of misaignment between the motor and the lead screw like a

Re: [Emc-users] A simple LinuxCNC system

On 29/04/2020 17:48, John Dammeyer wrote: Yes. Up until recently micro-stepper drives ran 10:1 but now they can do 256:1 although the jury is out on whether anything past 10:1 is useful. But that's a different discussion. The drivers I use have always had 128:1 but I've never found anything

Re: [Emc-users] A simple LinuxCNC system

> From: Jon Elson [mailto:el...@pico-systems.com] > On 04/29/2020 12:54 AM, John Dammeyer wrote: > > > > Here's my question for you. If the asynchronous pulse > > generator from your $1 chip has just created a pulse and > > the SERVO_PERIOD now wants to a new rate how do you set up > > the

Re: [Emc-users] A simple LinuxCNC system

> > > > Hi Gene, > > I'm just in learn mode trying to figure out how LinuxCNC works. Not > > worried about speed. So far, with various steppers when > actually used to drive machines I've found that if you can step at 20kHz you > are way beyond the torque capabilities of the motors. > > >

Re: [Emc-users] A simple LinuxCNC system

> Is the real time component of Linux CNC running all the tasks that are > > started with the loadrt with a 24uS period?In other words all loaded > > "loadrt tasks" have to finish within 24uS or the system will start to have > > jitter or miss events. > > > > No, only the functions that are

Re: [Emc-users] A simple LinuxCNC system

On 04/29/2020 12:54 AM, John Dammeyer wrote: Here's my question for you. If the asynchronous pulse generator from your $1 chip has just created a pulse and the SERVO_PERIOD now wants to a new rate how do you set up the frequency generator so that the next pulse is correctly spaced from the

Re: [Emc-users] A simple LinuxCNC system

On 04/29/2020 12:10 AM, John Dammeyer wrote: Hi Gene, I'm just in learn mode trying to figure out how LinuxCNC works. Not worried about speed. So far, with various steppers when actually used to drive machines I've found that if you can step at 20kHz you are way beyond the torque

Re: [Emc-users] A simple LinuxCNC system

On Wed, 29 Apr 2020 at 01:35, John Dammeyer wrote: The important constants come from the INI file: > Note that they don't have to. A very simple LinuxCNC configuration can omit the INI. But once you loadrt motmod, then you need an INI to pass it the axis data. Is the real time component of

Re: [Emc-users] A simple LinuxCNC system

On Wednesday 29 April 2020 01:10:54 John Dammeyer wrote: > > If using the parport in EPP mode, you can set a reset time > > separately, so you can step at the base thread rate. As far as motor > > speed is concerned, the speed limit is generally the speed limit of > > the opto stuff in the

Re: [Emc-users] A simple LinuxCNC system

> -Original Message- > From: Chris Albertson [mailto:albertson.ch...@gmail.com] > Sent: April-28-20 9:30 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] A simple LinuxCNC system > > On Tue, Apr 28, 2020 at 6:32 PM John Dammeyer > wrote: &

Re: [Emc-users] A simple LinuxCNC system

> > > If using the parport in EPP mode, you can set a reset time separately, so > you can step at the base thread rate. As far as motor speed is > concerned, the speed limit is generally the speed limit of the opto > stuff in the driver, and I've run steppeers laying on the table at > slightly

Re: [Emc-users] A simple LinuxCNC system

On Tue, Apr 28, 2020 at 6:32 PM John Dammeyer wrote: > > Will you share some code on how you accelerate from 0 to 15kHz stepping > rate on your $1 processor? > No code. that is the entire point. The microcontroller has built-in hardware the bigger PC or Raspberry Pi lacks. The way it works

Re: [Emc-users] A simple LinuxCNC system

On Tuesday 28 April 2020 21:29:39 John Dammeyer wrote: > > From: Chris Albertson [mailto:albertson.ch...@gmail.com] > > Sent: April-28-20 6:13 PM > > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] A simple LinuxCNC system > > > > > *For a

Re: [Emc-users] A simple LinuxCNC system

> > I couldn't find that reset mode in the hal_parport. At least not how you > > could have a step that lasted 5uS when the base period > was 35uS. How's that timing calculated? > > setp parport.0.reset-time 5000 > In the doc I linked earlier Ends up being reset_time in the reset_port()

Re: [Emc-users] A simple LinuxCNC system

> On 29 Apr 2020, at 12:34 pm, John Dammeyer wrote: > > > >> -Original Message- >> From: Peter C. Wallace [mailto:p...@mesanet.com] double step on this page may do that

Re: [Emc-users] A simple LinuxCNC system

> -Original Message- > From: Peter C. Wallace [mailto:p...@mesanet.com] > >> double step on this page may do that > >> >> > > > > > Nope. From the doc. "What is the

Re: [Emc-users] A simple LinuxCNC system

On Tue, 28 Apr 2020, John Dammeyer wrote: Date: Tue, 28 Apr 2020 19:09:00 -0700 From: John Dammeyer Reply-To: "Enhanced Machine Controller (EMC)" To: "'Enhanced Machine Controller (EMC)'" Subject: Re: [Emc-users] A simple LinuxCNC system As far as LinuxCNC go

Re: [Emc-users] A simple LinuxCNC system

> From: Phill C [mailto:phillcarte...@gmail.com] > > > On 29 Apr 2020, at 11:29 am, John Dammeyer wrote: > > > > As far as LinuxCNC goes, to me it appears the parallel port code given the > > steplen calculations there isn't a way to bring the step > pulse low again during the same

Re: [Emc-users] A simple LinuxCNC system

> > > > As far as LinuxCNC goes, to me it appears the parallel port code given the > > steplen calculations there isn't a way to bring the step > pulse low again during the same BASE_PERIOD interval which in the HAL file > example is 24uS not 10uS. Therefore I interpret the > step pulses to be

Re: [Emc-users] A simple LinuxCNC system

> On 29 Apr 2020, at 11:29 am, John Dammeyer wrote: > > As far as LinuxCNC goes, to me it appears the parallel port code given the > steplen calculations there isn't a way to bring the step pulse low again > during the same BASE_PERIOD interval which in the HAL file example is 24uS > not

Re: [Emc-users] A simple LinuxCNC system

> From: Chris Albertson [mailto:albertson.ch...@gmail.com] > Sent: April-28-20 6:13 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] A simple LinuxCNC system > > > > > *For a stepping motor driver with 10uStep per step that's still pretty > >

Re: [Emc-users] A simple LinuxCNC system

> > *For a stepping motor driver with 10uStep per step that's still pretty > well faster than it can actually turn. * No, you missed the point. With 10 uS per cycle, the motor can step in steps that are a multiple of 10uS long. So it can be 6000 uS or 6010 uS but never 6011 uS per step. It

[Emc-users] A simple LinuxCNC system

I've been studying the source code for the basic LinuxCNC system. One that doesn't require external intelligent hardware to augment a 4 core 2 GHz 64 bit processor. In other words the parallel port based system. Perhaps someone with more experience with the system can answer a few questions?