Several Operator Panels on Several NCUs, Distributed Systems (B3)2.2 Several operator panel fronts and NCUs with control unit management optionExtended Functions104 Function Manual, 01/2008, 6FC5397-1BP10-3BA0Permissible combinations in one installationIf a server (alarm/data management server) is configured in an M:N system, it also acts as amain control panel.Only one control unit in an M:N system can have the following properties:● Windows-HMI (HMI Advanced): Server and main control panelor● Non-Windows-HMI (HMI Embedded/HT6): Main control panelAny number of secondary control panels is possible.NoteIf the function Execution from external source is to be available, one operator panel in thesystem must be designated as a server.2.2.3 Configuration file NETNAMES.INIAs the hardware components can be freely combined (see Section "Hardware structure"), itis necessary to provide the system with information about the components which areconnected, how they are connected to each other, and how they interact.In particular, it is necessary to regulate the competition among the different control units forthe limited number of available interfaces (suppression, see Section "Suppression").For this purpose each PCU/HT6 has a configuration file NETNAMES.INI in which the theconfiguration parameters must be stored.