Currently I am developing new electroncis for one of our products using TMC5240 motor drivers. As recommended by the reference manual for StealthChop2, I want to determine the motor specific parameters for PWM_GRAD and PWM_OFS with the TMC5240-EVAL board and TMCL-IDE (version 4.3.0).
The motor parameters are:
Phase resistance: 40Ohm
Phase inductance: 23mH
Motor max. current: 0.32A
Holding torque: 0.18Nm
The TMC5240 operating conditions/settings are:
Supply voltage: 24V
Reference resistor: 48K
IRUN: 24 (0.14A)
IHOLD: 24 (0.14A)
PWM_REG: 4 (default)
PWM_FREQ: 0 (default)
As recommended for AT#1 step, I set IRUN and IHOLD identical and enabled StealthChop with both PWM_AUTOSCALE and PWM_AUTOGRAD enabled. I see PWM_OFS_AUTO = 238 and PWM_SCALE_SUM = 740 in the register browse after a short delay.
Afterwards I moved the motor for AT#2, but unfortunately it does not succeed. For example with a velocity of 60RPM, I get:
PWM_SCALE_SUM = 957
PWM_SCALE_AUTO = 52
PWM_GRAD_AUTO = 0
With 30RPM, I get:
PWM_SCALE_SUM = 809
PWM_SCALE_AUTO = 15
PWM_GRAD_AUTO = 0
I tried this step with different velocities, but I cannot fulfill the conditions given in the manual. PWM_GRAD_AUTO always remains zero and PWM_SCALE_AUTO does not regulate to zero.
Am I doing something wrong or is my motor exceeding the limits of StealthChop2?
