User Manual

TMCC160 TMCL Firmware Version 2.11 2018-FEB-08 | Document Revision 1.01 2018-FEB-08
© 2015 TRINAMIC Motion Control GmbH & Co. KG, Hamburg, Germany Terms of delivery and rights
to technical change reserved. Download newest version at: www.trinamic.com .
Read entire documentation; especially the 6 Supplemental Directives” (page 51).
I
2
T-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 a specific time span
depends on how often the current regulation and thus the I²t monitoring is invoked.
In order to configure the I
2
T monitor, the following parameters need to be
known and set accordingly:
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.
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.
NOTE:
Also note that the
I
²t exceed counter is increased once every second as long as
the actual
I
²t sum exceeds the
I
²t limit.
The
I
²t 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
I
²t limit can be determined as
follows:
The I²t limit can be determined as follows:
Thermal
Winding Time
Constant
of the
Motor
Configuration of
I
2
T Monitor

󰇟󰇠

󰇟󰇠


󰇟󰇠
is the desired average current

is the thermal winding time constant given by the motor
datasheet
Calculation Examples 5: Determine
I
²t limit