Double/Quadstepping Setup

RAyWB

Hi All,

is there someone who can help me with setup of double/quadstepping?
Firmware 092.6 (downloaded January 6th)

Hardware Mega2560 , Ramps 1.4 DRV8825 drivers.  Motors 0.9° Nema 17 for  direct Drive Extruders (2) .
Motors 1.8°Nema 23 (2A)  for x , y  Nema 17 (92oz) 1,8° for z Axis.
threaded Rods TR 16*4   for all axis.

Microstepping for x and y 1/4 (200 steps/mm) , 1/32 for z(1600 steps/mm).


I can Drive x and y up to 85 mm/s  each  but when i drive both i get stall at around 45 mm/s Feedrate.

basically for printing it´s enough but for travelling it´s too low .

i tried to change :

#define DOUBLE_STEP_DELAY  in a Range from 0 to 10 , (Optimum seems around 3 )
and
#define STEPPER_HIGH_DELAY in a Range from 1 to 4

but i seems Quadstepping isn´t working for me...

is anybody out there who solved similar problem ?


Thank´s in Advance

RAyWB

Repetier

If I remember right, this driver is quite picky about signal times and needs 1,8us per signal or it can not safely be assumed to be taken. SO stepper high delay should not be more then 2. More is wasting required comp. time.

With 0 delay you can reach about 40Khz with quadstepping. With delays it gets less. 85mm@200stepspermm => 17000Hz. Double step frequency is important here. With higher delays it must be decreased.

An alternative hardware solution would be RADDS+Due+RAPS128. That would allow 80000Hz without doublestepping. 160Khz with doublestepping.

The RAPS128 need no delays to work. The normal delay we have is long enough.

RAyWB

OK,  reduced stepper high delay now to1 and double step delay also to 1.

i can go up to 115 mm/s now when i drive single axis and around 95 when drive both axis.


i had to disable quadstepping because of earlier stall .

so i think my problem moved to the steppers now , they have to spin with more than 1400 rpm...

i read about usual rpms around 600 to 1000 maximum higher rpms is CNC Servomotor league......


Thanks for your support

RAyWB