How to reset pm500 Plc through onboard switches?
to reset the AC500 CPU:
Turn off the CPU.
Once you turned off, during the next power hold the RUN button, and will appear on the display MOD1.
In this way the speed of transmission rate will be reset to 19200 - 8N1, or the default parameters.
Later, reset the communication parameters, as Codesys, in "comunication parameter" as the default values.
Finally to clear the message MOD 1 select with the arrow keys on the front panel of the CPU mode 0 MOD.
Turn off the CPU, place the frontal white lever to STOP, turn on the CPU.
In this way are set automatically the default parameters in the PLC (as above), and to be able to connect to the CPU in online mode, set as above, from Codesys, in "comunication parameter" default parameters (19200 - 8N1)
Hope this help you