Repetier 0.91 rev 7, h bot uneven stepping

Hi everyone,

I'm getting problems setting up my custom printer with repetier 0.91 (used the online config wizard).
I am getting uneven stepping from the XY motors.

This is my setup:
Azteeg X3
Repetier firmware
Nema 17 motors
32 microstepping
320 mm/s configured for the motors
Drive system configured in repetier hbot

Everytime I move the axis, one motor is going slower. If I revert back to the 0.83 firmware, everything works again.
homing etc works.

Has anyone else experienced this ? and does anyone know what might be the culprit?

thanks

p.s. included the config file

Edited 1 time(s). Last edit at 05/17/2014 06:26PM by sam80.

I have exactly same issue here with RADDS board . have you found any fix for this?
thanks

The DRV8825 often used for 32 microstepping needs longer step high signals. So firmware is too fast. Solution is to set stepper high delay to 1 or 2us (RADDS). In online config tool you need to enable expert settings to see that option.

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I'm using A4988 stepsticks, I have changed STEPPER_HIGH_DELAY like you suggested but unfortunately it didn't fix the problem, still one of the motors stepping seems to be lower than the other one. It's a bit weird and I'm not sure if it's related directly to the stepping.. for example when I move the carriage in the X+ direction the feedrate seems to be approx. 2x faster than when moving it in the X- direction. Moving it in the y axis in any of the directions either +y or -y is resulting in moving the carriage in the y (+ or -) axis plus moving it towards -x direction. I think this thread is related to our issue [forums.reprap.org]
Do you have any further suggestions? Thanks for your help!

it looks like someone else has exactly same issue [www.youtube.com] , I have probably tried all possible settings in repetier firmware but without luck so far..

@Rav With RADDS you should set "Frequency, where steps get grouped in double steps" to 50000 or even 70000. Also I still think higher STEPPER_HIGH_DELAY should work. With xy gantrys the timing is a bit more critical so maybe even values of 3 are required.

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thanks Repetier, I have followed your suggestion and changed frequency for double steps to 50000 and 70000 and stepper_high_delay but it didn't change anything. I have even replaced stepsticks but this didn't change anything either :/. I have ordered another RAMPS board as i tested COREXY on my old one today and it worked perfectly. I'm not sure if this issue is related to the firmware or to RADDS board itself, I will try standard cartesian firmware to see if I will get even steps for both axis.

I'm getting even steps for all axis when changed gantry style to Cartesian printer so the issue has to be somehow related to the corexy part of the firmware, @Repetier, do you have any further suggestions? thanks!

has this been resolved?

It was never defect. It always was a speed problem - firmware was to fast for stepper driver. So for core xy you need a stepper high delay of 1 or 2 depending on your stepper driver and if you use avr or due.

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Good to know. Thanks for the fast response.

Hello,

what is exactly the reason that the core XY setup need a higher stepper high signal?

I have a DUE+Radds+RAPS128+CoreXY Setup (1/128 steps, ~3 µm/microstep)

If i set the stepper high signal from 2 to 3 or 4 the movement speed in X, Y is visible slower.
The movement seems also more jerky by higher delay values. In the slicer I have set alwas a printing speed of 100 mm/s.
But by 4 ms, it is definetly slower as 100 mm/s. By 2 ms it looks much faster.


Thank´s in advance.

For RAPS128 you do not need higher delays. Here a delay of 0 is enough. The problem are DRV... chips requiring 1.7us high signal to detect a step. Wie due and even with avr for core we are faster so they do not get recogniced and it looks like you are loosing steps.

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thank´s for your answer. Now it´s running much smoother without any stops by round-shapes.

Edited 1 time(s). Last edit at 08/16/2016 09:36AM by Flugrausch.