Datasheet

TMC2590 DATASHEET (V1.0 / 2019-FEB-22) 16
www.trinamic.com
Figure 6.2 shows the operating regions of CoolStep. The black line represents the SG measurement
value, the blue line represents the mechanical load applied to the motor, and the red line represents
the current into the motor coils. When the load increases, SG falls below SEMIN, and CoolStep
increases the current. When the load decreases and SG rises above (SEMIN + SEMAX + 1) x 32 the
current becomes reduced.
stallGuard2 reading
0=maximum load
motor current increment area
motor current reduction area
stall possible
SEMIN
SEMAX+SEMIN+1
time
motor current
current setting CS
(upper limit)
½ or ¼ CS
(lower limit)
mechanical load
current increment due to
increased load
slow current reduction due
to reduced motor load
load angle optimized load angle optimized
load
angle
optimized
Figure 6.2 CoolStep adapts motor current to the load
Four more parameters control CoolStep and one status value is returned:
Parameter
Description
Range
Comment
CS
Current scale. Scales both coil current values as
taken from the internal sine wave table or from
the SPI interface. For high precision motor
operation, work with a current scaling factor in
the range 16 to 31, because scaling down the
current values reduces the effective microstep
resolution by making microsteps coarser. This
setting also controls the maximum current value
set by CoolStep™.
0… 31
scaling factor:
1/32, 2/32, … 32/32
SEUP
Number of increments of the coil current for each
occurrence of an SG measurement below the
lower threshold.
0… 3
step width is:
1, 2, 4, 8
SEDN
Number of occurrences of SG measurements
above the upper threshold before the coil current
is decremented.
0… 3
number of StallGuard
measurements per
decrement: 32, 8, 2, 1
SEIMIN
Mode bit that controls the lower limit for scaling
the coil current. If the bit is set, the limit is ¼
CS. If the bit is clear, the limit is ½ CS.
0
Minimum motor
current: 1/2 of CS
1
1/4 of CS
Status word
Description
Range
Comment
SE
5-bit unsigned integer reporting the actual cur-
rent scaling value determined by CoolStep. This
value is biased by 1 and divided by 32, so the
range is 1/32 to 32/32. The value will not be
greater than the value of CS or lower than either
¼ CS or ½ CS depending on SEIMIN setting.
0… 31
Actual motor current
scaling factor set by
CoolStep:
1/32, 2/32, … 32/32