Re: How to increase the max slewing speed from 1.0 dps to 2.0 dps?


Howard Dutton
 

On Thu, Sep 22, 2022 at 02:43 AM, T.L. wrote:

Case 1:

With the total reduction ratio of 720, and AXIS1/2_DRIVER_MICROSTEPS to be 32,  and the AXIS1/2_DRIVER_MICROSTEPS_GOTO to be 8. The scope works very well at max slewing speed at 1dps (SLEW_RATE_BASE_DESIRED); but not any faster.

Max slewing speed with those settings on your hardware should be ~12 deg/s.

  I  have attached the Config-32.h (Config.h) for this case

 
Case 2:

It seems that if we reduce the total reduction ratio by half to 360; and use 64 micro steps (AXIS1/2_DRIVER_MICROSTEPS); all other to be same as the case 1; we should be able to have the same tracking accuracy (in theory)

Not the same tracking accuracy, generally 720:1 will be better.  The improvement of 64x vs. 32x is questionable at best, perhaps just a tiny gain.

but double the max slewing speed (SLEW_RATE_BASE_DESIRED) to 2.00 dps when the motor physically running at the same speed as the Case 1.
However, strangely. in this case the motors still visibly try to run at about twice of speed, and stalk most of the time.  I  have attached the Config-64.h (Config.h) for this case.

Perhaps you enabled runtime axis settings and the changes are being ignored?

// Settings for driver Microsteps, IRUN, Reverse, Limit Min, and Limit Max are stored in NV (EEPROM.) These runtime settings
// can be changed (or reverted to the defaults below) from the SmartWebServer's Config webpage.  If runtime axis settings are 
// enabled changes to these settings below may be ignored as runtime settings from NV (EEPROM) are used instead.

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