CAN-BUS Shield V1.2 - Power switch function

Hi to all,
on the shield there is a power switch: how does it works? When I switich on and off, the shield continue to work regulary, I cannot appreciate diferences between ON and OFF… :astonished:
I’m using the conneiction from the CAN terminal (green connector with 2 screws), could you clarify the function?

Thank you in advance, kind regards,

Hi, put switch to on when you want to power the system via 12V from the obd interface(or others).
If you power the system via a USB, you can forget the switch.