How can I reduce the CPU loads caused by pulse regulation with
pulse width modulation by decentralizing it?
If you are regulating the pulse with pulse width modulation,
the controller variable is converted into pulses on a rapid call
level. This puts a considerable load on the CPU. To avoid this
loading on the CPU, pulse width modulation can be
decentralized to the ET 200S with the "2 PULSE Module".
The SIMATIC Standard PID Control and Modular PID Control
software control packages and the controllers integrated in the
STEP 7 "Standard Library > PID Control Blocks" are suitable for
Please note the following points for linking the software
- Use the "2 PULSE Module" in "Pulse Width Modulation" mode.
- Use the "LMN_PER" variable output with the software
- For the "PWM Output Format" in the "2 PULSE Module" you must
set "SIMATIC S7 Analog Value" accordingly.
- The period should be selected to match the scanning time of the
- To increase the resolution, you can use 0.1 ms as the time
Software controller, Controller module