Re: [Emc-users] New stepper-servo --> Phase delay

2016-10-21 Thread dannym
They put a Cortex M0 on the module that sits on the board, along with the stepper driver and encoder. There's a greater latency inside the Cortex, it will likely have to respond to an interrupt thus have ISR latency. I presume they've got a PLL to prevent oscillation within the final step.

Re: [Emc-users] New stepper-servo --> Phase delay

2016-10-21 Thread Nicklas Karlsson
Best option is probably to generate stepper signal from hardware timer. 2016-10-21 8:17 GMT+02:00 Danny Miller : > The SPI comm of course has latency within a comm period. > > However, the pulse output must be super-fast. It supports up to 14500 > rpm, so if it's

Re: [Emc-users] New stepper-servo --> Phase delay

2016-10-21 Thread Danny Miller
The SPI comm of course has latency within a comm period. However, the pulse output must be super-fast. It supports up to 14500 rpm, so if it's 2000steps/rev the whole step cycle is 2ms, realistically like maybe 1/4 of that for latency? Danny On 10/19/2016 11:34 PM, Nicklas Karlsson wrote:

Re: [Emc-users] New stepper-servo --> Phase delay

2016-10-19 Thread Nicklas Karlsson
> > ... The lag also seemed to vary with velocity. > > > > > Most specifically, it was a lag in the encoder's loop to respond to > acceleration. > Velocity was fine, but when there is acceleration, the encoder's > velocity didn't change for a few milliseconds, then it had to produce > velocity

Re: [Emc-users] New stepper-servo

2016-10-19 Thread Jon Elson
On 10/19/2016 01:08 PM, Kirk Wallace wrote: > On 10/19/2016 10:53 AM, andy pugh wrote: >> On 19 October 2016 at 18:34, Roland Jollivet >> wrote: >> >>> While the devices have a high resolution, look at pg.7 for all the >>> non-linearity specs. So while you may discern

Re: [Emc-users] New stepper-servo

2016-10-19 Thread W. Martinjak
On 2016-10-19 12:08, Gene Heskett wrote: > That will give 16,383 discrete positions of > the screw per revolution of the screw, No, the max pulses are 1024 and the max steps are 4096. (pulses x 4) Putting the magnet on the pointer of an old dial gauge you have a nice surface feeler for

Re: [Emc-users] New stepper-servo

2016-10-19 Thread Kirk Wallace
On 10/19/2016 10:53 AM, andy pugh wrote: > On 19 October 2016 at 18:34, Roland Jollivet > wrote: > >> While the devices have a high resolution, look at pg.7 for all the >> non-linearity specs. So while you may discern 16 383 positions, you may be >> well over 50 counts

Re: [Emc-users] New stepper-servo

2016-10-19 Thread andy pugh
On 19 October 2016 at 18:34, Roland Jollivet wrote: > While the devices have a high resolution, look at pg.7 for all the > non-linearity specs. So while you may discern 16 383 positions, you may be > well over 50 counts in error. Possibly fixable in software.

Re: [Emc-users] New stepper-servo

2016-10-19 Thread Sarah Armstrong
I,m actually working on a unit to do exactly that Gene. Along with tool breakage sense Which is tending to be the pain, so I might make 2 units Sarah ⁣ Sent from BlueMail ​ On 19 Oct 2016, 11:13, at 11:13, Gene Heskett wrote: >On Wednesday 19 October 2016 01:01:18

Re: [Emc-users] New stepper-servo

2016-10-19 Thread W. Martinjak
On 2016-10-19 07:01, Danny Miller wrote: > But there's no mechanical connection to the motor, it's this new AS5047D > high speed, high resolution magnetic rotary position sensor: > > http://ams.com/eng/Products/Magnetic-Position-Sensors/Angle-Position-On-Axis/AS5047D It's just austrian art of

Re: [Emc-users] New stepper-servo

2016-10-19 Thread Gene Heskett
On Wednesday 19 October 2016 01:01:18 Danny Miller wrote: > A friend showed me this today, not powered up yet: > > https://www.kickstarter.com/projects/tropicallabs/mechaduino-powerful- >open-source-industrial-servo-m > > At first I was confused, it says it's a stepper, but with an encoder, > and