TMCM-1181 V3.0 Hardware Manual (Rev. 0.90 / 2015-JUL-10)
4
TRINAMICS UNIQUE FEATURES – EASY TO USE WITH TMCL
stallGuard2™ stallGuard2 is a high-precision sensorless load measurement using the back EMF on the
coils. It can be used for stall detection as well as other uses at loads below those which
stall the motor. The stallGuard2 measurement value changes linearly over a wide range
of load, velocity, and current settings. At maximum motor load, the value goes to zero or
near to zero. This is the most energy-efficient point of operation for the motor.
Load
[Nm]
stallGuard2
Initial stallGuard2
(SG) value: 100%
Max. load
stallGuard2 (SG) value: 0
Maximum load reached.
Motor close to stall.
Motor stalls
Figure 1.1 stallGuard2 load measurement SG as a function of load
coolStep™
coolStep is a load-adaptive automatic current scaling based on the load measurement via
stallGuard2 adapting the required current to the load. Energy consumption can be
reduced by as much as 75%. coolStep allows substantial energy savings, especially for
motors which see varying loads or operate at a high duty cycle. Because a stepper motor
application needs to work with a torque reserve of 30% to 50%, even a constant-load
application allows significant energy savings because coolStep automatically enables
torque reserve when required. Reducing power consumption keeps the system cooler,
increases motor life, and allows reducing cost.
0,9
Efficiency with coolStep
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0
Efficiency with 50% torque reserve
Efficiency
0
50
100
150
200
250
300
350
Velocity [RPM]
Figure 1.2 Energy efficiency example with coolStep
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