Chapter 4. CPU Operation162 PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual GFK-2222AD4.9.1 Passwords and Privilege Levels - Legacy ModePasswords are a configurable feature of the PACSystems CPU. Their use is optional and is set up usingthe programming software. Passwords provide different levels of access privilege for the CPU when theprogrammer is Online. Passwords are not used if the programmer is in Offline mode.The default state is no password protection. Each privilege level in the CPU may have a unique password;however, the same password can be used for more than one level. Passwords can be changed onlythrough the programming software.Passwords are one to seven ASCII characters in length.After passwords have been set up, access to the CPU via any communications path is restricted from thelevels at which the passwords are set, unless the proper password has been entered. Once a passwordhas successfully been accepted, access to the highest privilege level requested and below is granted (forexample, providing the password for level 3 allows access to functions at levels 1, 2, and 3).Note: The RUN/STOP Switch on the CPU overrides password protection. Even though theprogrammer may not be able to switch between Run and STOP Mode, the switch on the CPUcan do so.Privilege LevelsLevel Password Access Description4 Yes Write to configuration or logic. Configuration may only be written in STOP Mode; logic maybe written in STOP Mode or RUN Mode. Set or delete passwords for any level.Note: This is the default privilege for a connection to the CPU if no passwords are defined.3 Yes Write to configuration or logic when the CPU is in STOP Mode, including word-for-wordchanges, addition/deletion of program logic, and the overriding of discrete I/O.2 Yes Write to any data memory. This does not include overriding discrete I/O. The CPU can bestarted or stopped. CPU and I/O Fault Tables can be cleared.1 Yes Read any CPU data except for passwords. This includes reading fault tables, performingdatagrams, verifying logic/configuration, loading program and configuration, etc. from theCPU. None of this data may be changed. At this level, RUN/STOP Mode transitions from theprogrammer are not allowed.Protection Level Request from ProgrammerIn Legacy mode, upon connection to the CPU, the programmer requests the CPU to move to the highestnon-protected level.The programmer requests a privilege level change by supplying the new privilege level and the passwordfor that level. If the password sent by the programmer does not agree with the password stored in theCPU’s password access table for the requested level, the privilege level change is denied and a fault islogged in the CPU fault table. The current privilege level is maintained, and no change occurs. A requestto change to a privilege level that is not password protected is made by supplying the new level and anull password. A privilege change may be to a lower level as well as to a higher level.
