Servosila-Device-Reference-0xA020192

generator). A physical phenomena behind this effect is called "Back-Emf".
The phenomena is a foundation for the "sensorless" sensing of the rotor's
position. The controller continuously measures the Back-Emf voltages
using its electronic circuits, and applies some math to the measurements to
derive a position of the rotor. The math is what is actually called the
"Sensorless Observer" method.
The method works well at medium and high speeds. However, at low
speeds, the Back-Emf voltages turn out to be too low to be reliably
separated from a noise present in the electronic circuits. To counter the
noise issue, the "Sensorless Observer" discards voltage readings that are
lower than a certain voltage threshold. Effectively, the Sensorless Observer
is designed to wait until the Kickstart procedure manages to accelerate the
rotor to a speed high enough for the voltages to be reliably separated from
the noise.
The parameter "EMF Zero Speed Voltage (high watermark)", measured in
volts, specifies a threshold that the Back-Emf readings should reach in
order for Sensorless Observer to start providing reliable estimates of the
rotor position. The threshold should be aligned with "Kickstart: Speed
Limit" parameter since at that speed limit the motor is supposed to generate
Back-Emf voltages that are higher than the noise.
NOTE: The value for this parameter is automatically computed by the
"Spreadsheet" tool or by an auto-configuration procedure of the controller.
12
Sensorless Observer:
EMF Zero Speed
Voltage (low
watermark)
V The parameter "EMF Zero Speed Voltage (low watermark)", measured in
volts, specifies a threshold that Back-Emf readings should drop to in order
for Sensorless Observer to declare that its rotor position estimates are no
longer reliable.
NOTE: The value for this parameter is automatically computed by the
"Spreadsheet" tool or by an auto-configuration procedure of the controller.
FLOAT32,
0x2002,
0x63,
rw
Configuration - Features
The "Features" section provides means to customize the motor control laws to meet requirements of a specific
application.
# Parameter Units Description CANopen
1 Feature: Direct Drive
& Micro-Speeding
0 or 1 "Direct Drive" refers to an advanced technique of controlling brushless
motors at low speeds. The technique turns a brushless motor into a servo,
whenever an absolute encoder is attached to the motor (no speed reducer is
required). A typical direct drive motor is equipped with an encoder, but no
gearbox, yet it still provides a high precision of motion control.
Enabling the "Direct Drive" feature changes the way the controller manages
motion at low speeds. The motion at low speeds becomes much more
BOOL,
0x2004,
0x62,
rw
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