Configuration of PWM Outputs

The CPUs PM55x and PM564 provide up to 2 PWM output channels with a maximum frequency of 20 KHz. The parameter of PWM output channel of Onboard I/O must be configured before it can be used. User should take these steps to configure the PWM output function.

The 2 outputs can be controlled in 2 different configuration modes:

• Frequency mode
• Cycle time mode

Note

Relay-type outputs of Onboard I/Os cannot be used for PWM functionality.

The mode can be configured with the parameter Output X, PWM operation mode in the parameters list:

In frequency mode, by setting the FREQ and DUTY_CYCLE input variables of PWM channel, the Onboard I/O can generate 125 Hz to 20 kHz frequency with 0..100 % duty cycle waveform in output channels 2 and 3.

In the cycle time mode, by setting the CYCLE_TIME and CYCLE_DUTY input variables of PWM channel, the Onboard I/O can generate 125Hz to 20 kHz frequency with 0..100 % duty cycle waveform in output channels 2 and 3.

The PWM can be controlled via the corresponding mapped parameters in tab xDI+yDO I/O Mapping of the editor window. See Symbolic Names for Variables, Inputs and Outputs for further details on mapping Symbolic Names for Variables, Inputs and Outputs.

The channels have the following meaning:

Channel	Direction	Width	Meaning
State byte PWM X	Input	BYTE
Control byte PWM X	Output	BYTE
PWM X, frequency / cycle time	Output	DWORD
PWM X, duty cycle / duty time	Output	DWORD