Siemens SINAMICS S120 Function Manual page 291

kHz. The factory setting of the current controller cycle of the small Motor Module is 250 µs,
corresponding to a pulse frequency of 2 kHz.
Problem
For standard applications, the current controller cycle of the large Motor Module is increased up
to 500 µs, an integer multiple of the current controller cycle of 250 µs. As a consequence, the
pulse frequency of the large Motor Module is 1 kHz. As a consequence, the Motor Module in
Chassis format is no longer optimally utilized.
Remedy
Set the pulse frequency for the Motor Module Chassis to asynchronous operation with
p1800.10 = 12. Then increase the pulse frequency to 1.25 kHz with p1800. The current
controller cycle remains unchanged at 500 µs. The Chassis Motor Module is better utilized as
a result of the increased pulse frequency.
When setting the pulse frequency for the Motor Module Chassis, the Motor Module Booksize
is still operated in sync with the current control cycle of 250 µs at a pulse frequency of 2 kHz.
Boundary conditions for asynchronous pulse frequency
● A higher system utilization as a result of the activated gating unit for the asynchronous pulse
frequency (p1810.12 = 1) and the required current actual value correction (p1840 = 1)
causes:
– Halving the maximum number of axes that can be used
– A reduction in the current controller dynamic performance
● The maximum pulse frequency that can be set is limited to double the frequency of the
current controller cycle.
● The pulse procedure, where the pulse frequency can be freely adjusted, is not suitable for
a permanent-magnet synchronous motor without an encoder.
● If output reactors or filters are connected to a Motor Module in the Chassis format, when
dimensioning the reactors, the maximum pulse frequency must be taken into account and
for sine-wave filters, the minimum pulse frequency.
● The motor data identification must be performed with a current controller cycle of 250 µs or
500 µs with 2 kHz.
Overview of important parameters (see SINAMICS S120/S150 List Manual)
● p0115[0...6]
● p1800[0...n]
● p1810
● p1840[0...n]
Drive functions
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Sampling times for internal control loops
Pulse frequency setpoint
Modulator configuration
Actual value correction configuration
Vector control
6.23 Asynchronous pulse frequency
289