You can run this command when the simulation mode stops at a breakpoint⮫ “'Online' 'Simulation'”⮫ “'File' 'Printer setup'”. You will be given a dialog box with a list of the POU Call Stack.

The first POU is always PLC_PRG, because this is where the executing begins⮫ “POU (program organization unit)”.

The last POU is always the POU being executed.

After you have selected a POU and have pressed the 'Go to' button, the selected POU is loaded in its editor, and it will display the line or network being processed.