Sebastian,
Sebastian Kuzminsky wrote:
> Some other thoughts on the hm2-stepper config you linked in an earlier
> email:
>
> You dont need a BASE_PERIOD for hostmot2 - the base thread is in the FPGA.
>
> Your SERVO and TRAJ periods are both 100,000 ns, which is pretty
> aggressive, 1,000,000 ns is more typical. But if this works for you, great!
>
I know, you mentioned the BASE_PERIOD before. I have been playing around
a lot with these timings.
I had the SERVO and TRAJ periods set to different values; all the same
at 100,000 up to 2,000,000 or at different values (BASE < SERVO < TRAJ)
as suggested by the manual and with/without the BASE_PERIOD.
> For AXIS_0, your steplen and stepspace are both 2500 ns, so your max
> step rate is 200 K steps/second. Your scale is 640 steps/inch. This
> gives a max speed of 200K/640 = 312.5 inches/second. Wow. But you're
> specifying an [AXIS_0]MAX_VELOCITY of only 25... Something's not adding
> up there. I didnt check the other axes.
I wish that were true. The speed is in mm, not inches.
The steplen and stepspace values are the max. values for the stepper
controllers (400 kHz max. step frequency was given in the specs, I set
my system to use 200 kHz max). These are the hardware limitations of the
stepper controllers.
MAX_VELOCITY is determined by the stepper motors which is set to 25
mm/sec (or 1.5 m/min) for XYZ axes. This is how I think the files should
be set up: the stepspace/len values specifying the driver's limitations
and the MAX_VELOCITY specifying the motor/mechanics speed.
I am thinking of buying new motors/drivers that are able to run at
higher speeds but with a gantry of about 60 kilos these will never reach
the max 20 m/s (X travel is < 2 meters).
Thanks,
Rob
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