The IP address and subnet mask of the IED object in PCM600 must match the HMI and LAN ports of the protection relay (physical IED) to which the PC is connected. The PC and protection relay need to be on the same subnet.
There are two ways to set the IP address of an IED object in PCM600: on the first page of the wizard when including a new IED into a project or in the IP address box of the IED's Object Properties pane.
Choosing between the two ways depends on when the IP address is set. Typing the IP address via the IED's Object Properties pane is possible at any time while entering it via the configuration wizard can only be done when inserting the IED in online or offline mode.