Siemens SIMATIC S7-1500 System Manual page 131

Configuring
7.9 Configuration of digital inputs/outputs (X142)
Configuring Pulse width modulation (PWM) operating mode
To configure PWM operating mode, first define the required base frequency of pulse width
modulation. You can configure the base frequency as 1, 2, 4, 8 or 16 kHz. The selected base
frequency then applies to all channels of interface X142.
Figure 7-26 Base frequency of pulse width modulation
Now select the channels for PWM operating mode. If you want to configure very short
pulses, enable the high-speed output function.
Figure 7-27 Pulse width modulation channel
The selected digital output is switched with the selected base frequency and the switching
pattern from the control interface.
Inversion
You can invert the 24 V signal to adjust it to your process. By default, the signal is not
inverted.
High-speed output
If you select the high-speed output option, the digital output is switched alternately to
24 V DC and ground. Allows for extremely steep edges (output delay in the 1 μs range).
To allow signals pending very briefly to be output with pulse width modulation (for example,
level duration of 0.1 ms), you must operate the output as a high-speed output.
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SIMATIC Drive Controller
System Manual, 11/2019, A5E46600094-AA