ESP vs. Teensy and max slew speed


Chad Gray
 

I know max slew speed depends on at lot of things.  One is speed of the processor.

I started experimenting more with this SkyTrack satellite tracking software and i want to see if i can speed my mount up.

On my ESP based OnStep board i am getting a max of 1.4deg per sec.  

If i bump by steps per degree in config.h to a lower number I get some more speed (AKA i have to build a new mount made for speed).  How else can i increase slew speed?  Or do i need to build a PCB with a Teensy on it?  I think  i want to aim for 6 degrees per second.  4 is working pretty good, but i want to push it further.

Like one thing i want to experiment with is tracking ISS for doing radio communication with it.  I dont need arc second precision. I need degree precision.

Thanks!
Chad
--
Authorized OnStep Dealer and Creator of the CGE Pro Conversion Kit
https://graydigitalarts.com/


Dave Schwartz
 

Lower microsteps or lower physical reduction so slower or the same rate of toggling of STEP (i.e. keeping within the capabilities of the MCU) to the driver results in more movement at the motor. That and enough torque will get you all the speed you could possibly want.

On 2022-11-29 9:16 p.m., Chad Gray wrote:
I know max slew speed depends on at lot of things.  One is speed of the processor.

I started experimenting more with this SkyTrack <https://www.heavenscape.com/index.html> satellite tracking software and i want to see if i can speed my mount up.

On my ESP based OnStep board i am getting a max of 1.4deg per sec.

If i bump by steps per degree in config.h to a lower number I get some more speed (AKA i have to build a new mount made for speed). How else can i increase slew speed?  Or do i need to build a PCB with a Teensy on it?  I think  i want to aim for 6 degrees per second.  4 is working pretty good, but i want to push it further.

Like one thing i want to experiment with is tracking ISS for doing radio communication with it.  I dont need arc second precision. I need degree precision.

Thanks!
Chad
--
Authorized OnStep Dealer and Creator of the CGE Pro Conversion Kit
https://graydigitalarts.com/


 

I am interested to know why you only get 1.4 deg/sec, that is very poor speed for for ESP32. Can you tell us more about that mount, motors, reduction, stepsticks and configuration?


Chad Gray
 

Right now i am only on the bench.  I do not have an official mount, but the numbers i was using to only get 1.4 deg/sec

44444.44444
32 microsteps

17777.77778
32 microsteps

image.png



On Wed, Nov 30, 2022 at 10:13 AM Vladimir <cyberianice@...> wrote:
I am interested to know why you only get 1.4 deg/sec, that is very poor speed for for ESP32. Can you tell us more about that mount, motors, reduction, stepsticks and configuration?


--
Authorized OnStep Dealer and Creator of the CGE Pro Conversion Kit
https://graydigitalarts.com/


 

Hm, i don't think so. If you set STEP_WAVE_FORM to PULSE with that figures, and set desired goto speed to 1.95 deg/sec then max goto speed will be around 3.9 deg/sec (max is desired x2, set in App or SWS). ESP32 HAL will allow that because of multiplying by 1.6x that us/step when using PULSE. I tested that in my MaxESP3 and it worked, but I didn't like how my rig sounds when it goes 3.9 deg/sec.


 

Now I see from 1st post that you want to achieve 6 deg/sec. Then just use 1/16 microstepping together with PULSE wave form and should be no problem all the way up to 7.9 deg/sec.


Chad Gray
 

Well i want to go faster.  :)  Right now i am having good success with 4+ degrees per second when using this Sky Tracking software to track satellites.  This is all on the bench right now.

I only seem to be about to get 16us.  Let me re-flash my ESP with those settings and try again.  I want to make sure it was not me.

Chad

On Wed, Nov 30, 2022 at 5:27 PM Vladimir <cyberianice@...> wrote:
Now I see from 1st post that you want to achieve 6 deg/sec. Then just use 1/16 microstepping together with PULSE wave form and should be no problem all the way up to 7.9 deg/sec.


--
Authorized OnStep Dealer and Creator of the CGE Pro Conversion Kit
https://graydigitalarts.com/


Howard Dutton
 

What stepper drivers do you have?


Chad Gray
 

Yeah this is what i get with those settings.  16us 1.4.  So i am going to start dropping my steps per degree and microsteps so can get into 4 deg/sec.

 If i drop down to 10000 steps per degree and 16 micro steps i can get 6 deg/sec.  See second picture.  

Now i also wonder if a Teensy will report back to this Sky Tracking software the current position faster than the ESP computer?  YOu can see one of the checks it does is update frequency.
image.png



image.png

image.png

On Wed, Nov 30, 2022 at 5:53 PM Chad Gray <rchadgray@...> wrote:
Well i want to go faster.  :)  Right now i am having good success with 4+ degrees per second when using this Sky Tracking software to track satellites.  This is all on the bench right now.

I only seem to be about to get 16us.  Let me re-flash my ESP with those settings and try again.  I want to make sure it was not me.

Chad

On Wed, Nov 30, 2022 at 5:27 PM Vladimir <cyberianice@...> wrote:
Now I see from 1st post that you want to achieve 6 deg/sec. Then just use 1/16 microstepping together with PULSE wave form and should be no problem all the way up to 7.9 deg/sec.


--
Authorized OnStep Dealer and Creator of the CGE Pro Conversion Kit
https://graydigitalarts.com/


Chad Gray
 

What I am testing with is Nema17.  This is all bench testing.  I am just playing with numbers and asking the Sky Tracking software to try to keep up with a satellite.

I will post my results as a video soon, but if a teensy can return the position more frequently than a ESP  that may also help me track satellites.

Chad

On Wed, Nov 30, 2022 at 6:13 PM Howard Dutton <hjd1964@...> wrote:
What stepper drivers do you have?


--
Authorized OnStep Dealer and Creator of the CGE Pro Conversion Kit
https://graydigitalarts.com/


Chad Gray
 

OH drivers.. sorry LV8729


On Wed, Nov 30, 2022 at 6:49 PM Chad Gray <rchadgray@...> wrote:
What I am testing with is Nema17.  This is all bench testing.  I am just playing with numbers and asking the Sky Tracking software to try to keep up with a satellite.

I will post my results as a video soon, but if a teensy can return the position more frequently than a ESP  that may also help me track satellites.

Chad

On Wed, Nov 30, 2022 at 6:13 PM Howard Dutton <hjd1964@...> wrote:
What stepper drivers do you have?


--
Authorized OnStep Dealer and Creator of the CGE Pro Conversion Kit
https://graydigitalarts.com/


Howard Dutton
 

On Wed, Nov 30, 2022 at 03:50 PM, Chad Gray wrote:
OH drivers.. sorry LV8729
If this is a MaxESP3 you could mode switch using M2 only (M0 and M1 must remain the same between modes for both Axis1 and Axis2.)

4x slewing and 64x tracking should work.


Chad Gray
 

Still waiting on some parts to build my first MaxESP.

I will read up on mode switching.

Chad

On Wed, Nov 30, 2022 at 7:34 PM Howard Dutton <hjd1964@...> wrote:
On Wed, Nov 30, 2022 at 03:50 PM, Chad Gray wrote:
OH drivers.. sorry LV8729
If this is a MaxESP3 you could mode switch using M2 only (M0 and M1 must remain the same between modes for both Axis1 and Axis2.)

4x slewing and 64x tracking should work.


--
Authorized OnStep Dealer and Creator of the CGE Pro Conversion Kit
https://graydigitalarts.com/


Howard Dutton
 

In addition to all of this, with regard to slew speeds the latest OnStepX has two changes:

1. The ESP32 libraries version 2.0.5 are not capable of slew speeds as ESP32 libraries 2.0.0 are.  Under 2.0.0 you can use >= 16uS step rates (both Axes.)  Under 2.0.5 you can use >= 40uS step rates (both Axes.)  That's for square wave mode, pulse is 1.6x faster.

2. I changed how using different step rates for Axis1 vs. Axis2 are combined into an allowed average (Integrated) step rate.  The prior method was deeply flawed...

Step Step Integrated Integrated
rate Axis1 rate Axis2 Old method New method
uS uS uS uS
16 1 4.3 0.9
16 2 4.5 1.8
16 4 5.0 3.2
16 8 6.0 5.3
16 16 8.0 8.0
16 32 12.0 10.7
16 64 20.0 12.8
16 128 36.0 14.2
16 256 68.0 15.1


Howard Dutton
 

On Thu, Dec 1, 2022 at 03:38 AM, Howard Dutton wrote:
1. The ESP32 libraries version 2.0.5 are not capable of slew speeds as ESP32 libraries 2.0.0 are. 
And 2.0.0 is/was recommended but I found trouble with the reliability of WiFi which 2.0.5 fixed, so now perhaps 2.0.5 should be recommended and just live with the slowdown and hope it gets addressed in the future.


Howard Dutton
 

On Thu, Dec 1, 2022 at 03:45 AM, Howard Dutton wrote:
And 2.0.0 is/was recommended but I found trouble with the reliability of WiFi which 2.0.5 fixed, so now perhaps 2.0.5 should be recommended and just live with the slowdown and hope it gets addressed in the future.
This is appealing as 2.0.5, I believe, will be the best choice for the SHC and SWS as well.


Drew 🔭📷🚴‍♂️
 

On Thu, Dec 1, 2022 at 06:53 AM, Howard Dutton wrote:
This is appealing as 2.0.5, I believe, will be the best choice for the SHC and SWS as well.
I am using v2.0.5 in OnStepX, SHC and SWS without issue. I do not see the slowdown with my real world application. LXD75 mount, MaxESP3, TMC5160, 30720 steps, 64/8 microstepping, 2.50 slew base rate.  Axis1=Axis2 so I did not see the "averaging math" problem.

I get the 5.0 degrees/second GoTo rate without problems, plenty fast in the real world.

Hopefully v2.06 will fix the slew speed problem. However, if true to form, it will introduce some new ones.


Chad Gray
 

OK the teensy is fast.  :)  The SWS runs faster, ASCOM seems to run faster.  I have not tried the Android app yet, but i bet it runs faster also.

I built the MiniPCB with Teensy 4.0.  I might have to build some more.  The extra cost of the teensy might be worth it!

This is both RA and DEC with LV8729 drivers 16 microsteps 10000 steps per degree.
#define SLEW_RATE_BASE_DESIRED        4.0 //

I was able to get 8 on the ASCOM driver and 12.5us.

I will load same settings back on ESP32, but if i remember correctly i maxed out at 16us and 6.1 deg/sec.
image.png


On Thu, Dec 1, 2022 at 10:35 AM Drew 🔭📷🚴‍♂️ <drewbolce@...> wrote:
On Thu, Dec 1, 2022 at 06:53 AM, Howard Dutton wrote:
This is appealing as 2.0.5, I believe, will be the best choice for the SHC and SWS as well.
I am using v2.0.5 in OnStepX, SHC and SWS without issue. I do not see the slowdown with my real world application. LXD75 mount, MaxESP3, TMC5160, 30720 steps, 64/8 microstepping, 2.50 slew base rate.  Axis1=Axis2 so I did not see the "averaging math" problem.

I get the 5.0 degrees/second GoTo rate without problems, plenty fast in the real world.

Hopefully v2.06 will fix the slew speed problem. However, if true to form, it will introduce some new ones.


--
Authorized OnStep Dealer and Creator of the CGE Pro Conversion Kit
https://graydigitalarts.com/


Chad Gray
 

OH true.. no bluetooth to test the android app with Teensy.  :)


On Thu, Dec 1, 2022 at 5:15 PM Chad Gray <rchadgray@...> wrote:
OK the teensy is fast.  :)  The SWS runs faster, ASCOM seems to run faster.  I have not tried the Android app yet, but i bet it runs faster also.

I built the MiniPCB with Teensy 4.0.  I might have to build some more.  The extra cost of the teensy might be worth it!

This is both RA and DEC with LV8729 drivers 16 microsteps 10000 steps per degree.
#define SLEW_RATE_BASE_DESIRED        4.0 //

I was able to get 8 on the ASCOM driver and 12.5us.

I will load same settings back on ESP32, but if i remember correctly i maxed out at 16us and 6.1 deg/sec.
image.png

On Thu, Dec 1, 2022 at 10:35 AM Drew 🔭📷🚴‍♂️ <drewbolce@...> wrote:
On Thu, Dec 1, 2022 at 06:53 AM, Howard Dutton wrote:
This is appealing as 2.0.5, I believe, will be the best choice for the SHC and SWS as well.
I am using v2.0.5 in OnStepX, SHC and SWS without issue. I do not see the slowdown with my real world application. LXD75 mount, MaxESP3, TMC5160, 30720 steps, 64/8 microstepping, 2.50 slew base rate.  Axis1=Axis2 so I did not see the "averaging math" problem.

I get the 5.0 degrees/second GoTo rate without problems, plenty fast in the real world.

Hopefully v2.06 will fix the slew speed problem. However, if true to form, it will introduce some new ones.


--
Authorized OnStep Dealer and Creator of the CGE Pro Conversion Kit
https://graydigitalarts.com/


Howard Dutton
 

On Thu, Dec 1, 2022 at 02:15 PM, Chad Gray wrote:
I was able to get 8 on the ASCOM driver and 12.5us.
The T4.0 is much faster than that, should be ok down to 1.5us.