Boundary Conditions For Asynchronous Pulse Frequency - Siemens Sinamics S120 Function Manual

Activating the function
● You can activate the function with p1810.12 = 1
● Set the pulse frequency with p1800 in 50 Hz increments to the desired pulse frequency.
● Activate the current actual value correction with p1840 = 0.
Application example
Situation:
A large (>250kW) Motor Module in the chassis format and a small (< 250kW) Motor Module,
e.g. in the booksize format, are to be connected to one DRIVE-CLiQ line.
The factory setting of the current controller cycle of the small Motor Module is 250 µs,
corresponding to a pulse frequency of 2 kHz. The factory setting of the current controller
cycle of the large Motor Module is 400 µs, corresponding to a pulse frequency of 1.25 kHz.
Problem:
For standard applications, the current controller clock cycle of the large Motor Modules 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 the chassis format is no longer optimally utilized.
Solution:
Activate separation of pulse frequency and current controller cycle for the large Motor
Module.
The Motor Module Booksize is still operated in synchronism with the current control cycle of
250 µs at a pulse frequency of 2 kHz.
For the Motor Module in the chassis format, set the pulse frequency to asynchronous
operation with p1800.12 = 1. Then increase the pulse frequency of the Motor Module
Chassis to 1.25 KHz using p1800, while the current controller clock cycle remains at 500 µs.
The Motor Module Chassis is better utilized as a result of the increased pulse frequency.
4.26.2

Boundary conditions for asynchronous pulse frequency

1. A higher system utilization as a result of the activated gating unit for the asynchronous
2. The maximum pulse frequency that can be set is limited to double the frequency of the
3. The pulse technique, where the pulse frequency can be freely adjusted, is not suitable for
Drive functions
Function Manual, (FH1), 01/2012, 6SL3097-4AB00-0BP2
The maximum pulse frequency that can be set is twice the current controller clock cycle.
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
current controller cycle.
a permanent-magnet synchronous motor without an encoder.
Vector control
4.26 Asynchronous pulse frequency
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