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4.6 RAS Table
The RAS table contains communication module information. Figure 4-13 shows the structure of
the RAS table.
CPCS
• The figures 0 through 3F correspond to the CPL numbers of the module. A set bit indicates that
the module is communicating with another module.
0: The LADDER switch of the CPU identified with the set CPL number is set to STOP; the cable
is broken or not connected; power is not supplied; or the transmission area for the module
having the CPL number is not yet set.
1: Data is being received normally from the module identified with the set CPL number.
• CP indicates detection of primary ring disconnection and CS detection of secondary ring
disconnection.
0: The module immediately preceding the local module is normal.
1: Disconnection occurred in the module immediately before the local module or the immediately
preceding module is inactive or faulty.
The communicating module is monitoring other modules. When the communicating module
receives data from another module, it judges that this module is communicating with another and
sets the associated bit of the RAS table. If it does not receive data within a fixed time period, the
communicating module judges that the other module is inactive and clears the associated bit of the
RAS table.
The bit corresponding to the local module indicates the operating status of the module. This bit is
set when the local module is operating normally. It is cleared when the module stops abnormally.
The above shows that the failures listed in Table 4-3 can be detected from the RAS table.
15
2
0 1 2
0 1 2
Figure 4-13 Structure of RAS Table
3D 3E 3F
3D 3E 3F
Not used
4-11
4 USER GUIDE
0
2
Main ring
Subring
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