Siemens CPU 948 - Structure of DX 0

7.2 Structure of DX 0
DX 0 consists of three parts:
•• the start ID for DX 0 (DW 0, 1 and 2) ,
•• several fields of different lengths (depending on the number of
parameters)
and
•• the end ID.
Start ID ASCII characters MASKX0 in DW 0 to DW 2
Field A field in DX 0 consists of one to n data words. These contain the
following:
•• the field ID,
•• the field length
and
•• the field parameters.
Field ID The field ID specifies the meaning of the parameters following it.
Each field is assigned to a specific system program section or to a
specific system function (e.g. the field ID "04" identifies the parameter
field for cyclic program execution).
Field length The field length specifies how many data words are occupied by the
parameters.
Parameters The possible parameters are listed in Section 7.3. The specified
numerical values are in hexadecimal format (KH).
End ID This indicates the end of DX 0 with EEEEH in the last data word.
Structure of DX 0
CPU 948 Programming Guide
C79000-G8576-C848-04
7 - 5