Datasheet

TMC4671 Datasheet • IC Version V1.3 | Document Revision V2.00 • 2020-Apr-17
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positioning to have a benefit from higher resolution using electrical angles. This is because each period -
electrical or mechanical - is normalized to 2
16
= 65536 positions.
6.5 Modes of Operation - (Open Loop), Torque, Velocity, Positioning
The TMC4671 can operate in torque mode, velocity mode, or position mode. The control loops (current,
velocity, position) are cascaded, thus the outer loops depend on the tuning of the inner loops. So, the
current loop must be adjusted first. The velocity loop must be adjusted after the current control loop is
adjusted. The position control loop must be adjusted last.
6.6 Controller Tuning
PI controller tuning is described throughout the control theory literature. In general there are two main
strategies to tune the controllers. First strategy is to observe controller step response for different
parameter sets and tune parameters to fit dynamics and settling time. With this approach sampling target
and actual value as well as controller output (check for saturation) at fixed frequency is recommended.
The USB-2-RTMI adapter in combination with the TMCL-IDE provide tuning tools to support this strategy.
Another approach is to identify controller plant parameters and calculate controller parameters from these
parameters. This is also supported by the TMCL-IDE for the current control loop. For the other control
loops the first strategy is recommended.
7 Register Map
The TMC4671 has an register address range of 128 addresses with registers up to 32 bit data width. Some
registers hold 32 bit data fields, some hold 2 x 16 bit data fileds and other hold combinations of different
data fields with individual data types. Data fields need to extracted by masking and shifting after read
from a TMC4671 register within the application. Data fields need to be composed by masking and shifting
by the application before writing into a TMC4671 register. Please check TRINAMIC’s API to reduce software
development efforts. This section describes the register bank of the TMC4671.
Section 7.1 gives an overview over all registers. It is is intended to give an initial over view of all registers.
Section 7.2 is the detailed reference of all registers and the register fields.
Section 7.3 gives the description of power-on-reset default values of all registers.
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