TMC5160 DATASHEET (Rev. 1.08 / 2018-NOV-19)
57
AUTOMATIC TUNING TIMING AND BORDER CONDITIONS
Step Parameter
AT#1 PWM_
OFS_AUTO
Conditions
Required Duration
≤ 2^20+2*2^18 tCLK,
≤ 130ms
- Motor in standstill and actual current scale (CS) is
identical to run current (IRUN).
- If standstill reduction is enabled, an initial step
pulse switches the drive back to run current, or set
IHOLD to IRUN.
(with internal clock)
- Pin VS at operating level.
Attention: Driver may reduce chopper frequency during
AT#1. Use reduced standstill current IHOLD<IRUN to
prevent extended periods of time at lower chopper
frequency
- Move motor at a velocity, where a significant 8 fullsteps are required
AT#2 PWM_
amount of back EMF is generated and where the full for a change of +/-1.
GRAD_AUTO
run current can be reached. Conditions:
For a typical motor with
- 1.5 * PWM_OFS_AUTO
4 * PWM_OFS_AUTO
<
PWM_SCALE_SUM
<
PWM_GRAD_AUTO
optimum at 50 or less, up
to 400 fullsteps are
required when starting
from default value 0.
-
PWM_SCALE_SUM < 255.
Hint: A typical range is 60-300 RPM.
Hint:
Determine best conditions for automatic tuning with the evaluation board.
Use application specific parameters for PWM_GRAD and PWM_OFS for initialization in firmware to provide
initial tuning parameters.
Monitor PWM_SCALE_AUTO going down to zero during the constant velocity phase in AT#2 tuning. This
indicates a successful tuning.
Attention:
Operating in stealthChop without proper tuning can lead to high motor currents during a deceleration
ramp, especially with low resistive motors and fast deceleration settings. Follow the automatic tuning
process and check optimum tuning conditions using the evaluation board. It is recommended to use
an initial value for settings PWM_OFS and PWM_GRAD determined per motor type.
Protect the power stage and supply by additionally tuning the overcurrent protection.
Known Limitations:
Successful completion of AT#1 tuning phase is not safely detected by the TMC5160. It will require
multiple motor start / stop events to safely detect completion.
Successful determination is mandatory for AT#2: Tuning of PWM_GRAD will not start when AT#1 has
not completed.
Successful completion of AT#1 and AT#2 only can be checked by monitoring PWM_SCALE_AUTO
approaching 0 during AT#2 motion.
Solution a):
Complete automatic tuning phase AT#1 process, by using a slow-motion sequence which leads to
standstill detection in between of each two steps. Use a velocity of 8 (6 Hz) or lower and execute
minimum 10 steps during AT#1 phase.
Solution b):
Store initial parameters for PWM_GRAD_AUTO for the application. Therefore, use the motor and
operating conditions determined for the application and do a complete automatic tuning sequence
(refer to a)). Store the resulting PWM_GRAD_AUTO value and use it for initialization of PWM_GRAD.
With this, tuning of AT#2 phase is not mandatory in the application and can be skipped. Automatic
tuning will further optimize settings during operation. Combine with a) if desired.
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