TMC262-EVAL 参数 Datasheet PDF下载

TMC262 DATASHEET (Rev. 2.07 / 2013-FEB-14)

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5.1 Tuning coolStep

Before tuning coolStep, first tune the stallGuard2 threshold level SGT, which affects the range of the

load measurement value SG. coolStep uses SG to operate the motor near the optimum load angle of

+90°.

The current increment speed is specified in SEUP, and the current decrement speed is specified in

SEDN. They can be tuned separately because they are triggered by different events that may need

different responses. The encodings for these parameters allow the coil currents to be increased much

more quickly than decreased, because crossing the lower threshold is a more serious event that may

require a faster response. If the response is too slow, the motor may stall. In contrast, a slow

response to crossing the upper threshold does not risk anything more serious than missing an

opportunity to save power.

coolStep operates between limits controlled by the current scale parameter CS and the SEIMIN

bit.

5.1.1 Response Time

For fast response to increasing motor load, use a high current increment step SEUP. If the motor load

changes slowly, a lower current increment step can be used to avoid motor current oscillations. If the

filter controlled by SFILT is enabled, the measurement rate and regulation speed are cut by a factor of

four.

5.1.2 Low Velocity and Standby Operation

Because stallGuard2 is not able to measure the motor load in standstill and at very low RPM, the

current at low velocities should be set to an application-specific default value and combined with

standstill current reduction settings programmed through the SPI interface.

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