When doing system upgrade for Vision PLC, there is a message while OS is being installed:
For System Upgrade PC should be connected to PLC via COM 1
Should be, or has to be? OS can also be upgraded vie Ethernet, so why is it recommended to be done over serial port? Why is this note there? Is it technical reason or practical, like if something goes wrong PLC will be in your reach and you won't have bricked unit in remote location.