Siemens SIMATIC S7-1500 System Manual page 191

Pulse width modulation (PWM) is based on the specification of a base frequency of 1, 2, 4, 8
or 16 kHz. You can alter the base frequency in terms of period and pulse-pause ratio over the
control interface (32-bit value). The bit pattern is shown in each base period. The base period
is defined on the basis of the base frequency. A "0" is LOW and a "1" is HIGH.
Examples
Base frequency: 1 kHz → Base period: 1 ms
1111 0000 0000 0000 1111 0000 0000 0000
Time period: 500 µs; 375 µs LOW; 125 µs HIGH
Figure 9-28 Pulse width modulation
Base frequency: 1 kHz
1111 1111 1111 1111 0000 0000 0000 0000
Time period: 1 ms; 500 µs LOW; 500 µs HIGH
1111 1111 0000 0000 0000 0000 0000 0000
Time period: 1 ms; 750 µs LOW; 250 µs HIGH
1111 0000 1111 0000 1111 0000 1111 0000
Time period: 250 µs; 125 µs LOW; 125 µs HIGH
Base frequency: 2 kHz
1010 1010 1010 1010 1010 1010 1010 1010
Time period: 31.25 µs; 15.625 µs LOW; 15.625 µs HIGH
SIMATIC Drive Controller
System Manual, 11/2023, A5E46600094-AD
9.9 Configuration of digital inputs/outputs (X142)
Configuring
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