User manual

PD-1021 TMCL Firmware V1.19 Manual (Rev. 1.01 / 2012-JUL-30) 65
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4.2 stallGuard2
The module is equipped with TMC262 motor driver chip. The TMC262 features load measurement that can
be used for stall detection. stallGuard2 delivers a sensorless load measurement of the motor as well as a
stall detection signal. The measured value changes linear with the load on the motor in a wide range of
load, velocity and current settings. At maximum motor load the stallGuard2 value goes to zero. This
corresponds to a load angle of 90° between the magnetic field of the stator and magnets in the rotor.
This also is the most energy efficient point of operation for the motor.
Stall detection means that the motor will be stopped when the load gets too high. It is configured by
axis parameter #174.
Stall detection can also be used for finding the reference point. Do not use RFS in this case.
4.3 coolStep Related Axis Parameters
The figure below gives an overview of the coolStep related parameters. Please have in mind that the
figure shows only one example for a drive. There are parameters which concern the configuration of the
current. Other parameters are for velocity regulation and for time adjustment.
It is necessary to identify and configure the thresholds for current (I6, I7 and I183) and velocity (V182).
Furthermore the stallGuard2 feature has to be adjusted and enabled (SG170 and SG181).
The reduction or increasing of the current in the coolStep area (depending on the load) has to be
configured with parameters I169 and I171.
In this chapter only basic axis parameters are mentioned which concern coolStep and stallGuard2. The
complete list of axis parameters in chapter 4 contains further parameters which offer more configuration
possibilities.
Velocity
Time
T214
coolStep™ area
I7
I7
area without coolStep™
coolStep™ adjustment points and thresholds
SG170
SG181
V182
I6
I183 I183
Current
V123 Velocity and parameter
I123 Current and parameter
T123 Time parameter
I7
I6
I183
I6/2*
* The lower threshold of the coolStep™ current can be adjusted up to I6/4. Refer to parameter 168.
The current depends on
the load of the motor.
SG123 stallGuard2™ parameter
Figure 4.1: coolStep adjustment points and thresholds