Siemens CPU 948

System data words
RS 75 to RS 78
System message
The entries in system data words RS 75 to RS 78 refer to the error that
occurred last. The message consists of four system data words with the
following structure:
15 0
RS 75 Error number Parameter type E F04BH
RS 76 Parameter 1 E F04CH
RS 77 Parameter 2 E F04DH
RS 78 Parameter 3 E F04EH
RS 75 The high byte contains the error number which classifies the error.
The error number assigns the error to one of the following three areas:
Error groups
•• 01H to 2FH: user error
•• 30H to 3FH: error in DX 0 or DB 1,
•• 40H system error
Parameter type The low byte contains the parameter type that describes the structure
of the succeeding parameter block in RS 76 to RS 78. The parameter
types from 00H to 10H exist. The structure of the parameter field is
described later.
The two following tables list the error groups "general errors" and
"errors in DX 0 or DB 0".
Bit Assignment of the System Data Words
CPU 948 Programming Guide
C79000-G8576-C848-04
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