Microstepping while guiding/moving (Arduino)

[N-DD]

Hi,

I am noticing uneven movements when auto guiding (PHD2) or moving the mount using the arrow keys from the EQMOD panel (speed 1x). I am using an Arduino Mega2560 and microstepping 1/8 or 1/16. It seems like AstroEQ does not use the correct microstepping when guiding or moving (the motors rotate at a much higher speed than they are supposed to and noticeably rougher). My setup: AstroEQ on Arduino Mega2560 (latest Config utility v 7.3), Pololu DRV8255, 200 steps/rev. 1:10 steppers, 1:144 worm (Vixen GP).

Thanks,

Nico

[TCWORLD]

Hi Nico,

What connections have you made between the mode pins and the DRV8825 board? There were some changes in V7.3 in the pin connections to bring the Arduino Mega design in line with the ATMega162 variant.

[N-DD]

Hi,

I am using the following connections: RA: Mode 0 - Pin 15 Mode 1 - Pin 16 Mode 2 - Pin 17

Dec: Mode 0 - Pin 20 Mode 1 - Pin 19 Mode 2 - Pin 18

Are these the right ones? During normal tracking the RA stopper moves smoothly, I only get rough movements when guiding or when using the arrow buttons. Alternatively, could it be something related to the pulse duration (which might be not optimal for my steppers)?

Thanks

[TCWORLD]

Those look correct. There isn't any difference between tracking, guiding or using the arrow buttons - unless you are trying to guide at >200x the sidereal rate - which is what it takes to get the microstepping mode to change.

What is your setup? (gear ratios, etc.)

[N-DD]

I am using 200 steps/revolution stepper, 16x microstepping. The motors have 1:10 gears and the worm ratio is 1:144. I have tried setting different guiding rates, from 0.1x to 0.9x but that did not solve the issue. Is it possible to access the current microstepping value while AstroEQ is running?

[TCWORLD]

The microstepping values are fixed and can only be changed through the configuration utility.

The thing is the microstepping value doesn't get changed while running, so guiding should be no different than tracking or using the NESW buttons - in fact the commands sent are identical for all three. The only exception is for ustep modes >1/8, go-to movements and slews which are greater than 200x speed cause EQMOD to issue a high-speed movement which changes the microstepping mode to increase Torque, after which movement, the mode changes back immediately.

Could you record a video of the stepper motors?

[N-DD]

Hi,

I just did a clean install of ASCO/EQMOD and the issue is gone: now the movements are smooth. Sorry for opening the issue, it seems it was a different problem!

Thanks anyway for the info and the support.

[TCWORLD]

Glad its all sorted :+1: