S7 300 Memory Reset
Visit the following site for manual, .
http://manuali.eltex.biz/Manuali_Siemens/S73bhb_e.pdf
Page 132 of the manual gives graphical version of reset
[FONT="]Resetting the CPU Memory Using the Mode Selector[/FONT]
[FONT="]To reset the CPU memory using the mode selector , do the following (also see Fig. 8-7):[/FONT]
[FONT="]1. Turn the key to the STOP position.[/FONT]
[FONT="]2. Turn the key to the MRES position. Hold the key in this position until the STOP LED lights up for the second time (this takes 3 seconds).[/FONT]
[FONT="]The CPU acknowledges the reset request.[/FONT]
[FONT="]3. Within 3 seconds, you must turn the key back to the MRES position and hold it in this position until the STOP-LED flashes (at 2 Hz). [/FONT]
[FONT="]When the CPU has completed the reset, the STOP LED stops flashing and remains lit.[/FONT]
[FONT="]The CPU has performed the reset.[/FONT]