User manual
TMCM-1640 TMCL Firmware V2.00 Manual (Rev. 2.00 / 2012-JUL-31) 54
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8 Temperature Calculation
Axis parameter 152 delivers the actual ADC value of the motor driver. This ADC value can be converted to a
temperature in °C as follows:
Example 1: Example 2:
ADC = 1000 ADC = 1200
R
NTC
≈ 6.81 R
NTC
≈ 5.31
T ≈ 35 T ≈ 42
9 I²t Monitoring
The I²t monitor determines the sum of the square of the motor current over a given time. The integrating
time is motor specific. In the datasheet of the motor this time is described as thermal winding time
constant and can be set for each module using axis parameter 25. The number of measurement values
within this time depends on how often the current regulation and thus the I²t monitoring is invoked. The
value of the actual I²t sum can be read by axis parameter 27. With axis parameter 26 the default value for
the I²t limit can be changed (default: 211200). If the actual I²t sum exceeds the I²t limit of the motor, flag 17
(in axis parameter 156) is set and the motor pwm is set to zero as long as the I²t exceed flag is set. The
actual regulation mode will not be changed. Furthermore, the I²t exceed counter is increased once every
second as long as the actual I²t sum exceeds the I²t limit. The I²t exceed flag can be cleared manually using
parameter 29 but only after the cool down time given by the thermal winding time constant has passed.
The I²t exceed flag will not be reset automatically. The I²t limit can be determined as follows:
is the desired average current
is the thermal winding time constant given by the motor datasheet
Example:
I²t limits for an average current of a) 1A, b) 2A, c) 3A and d) 4A over a thermal winding time of 13,2s.
a)
b)
c)
d)