Technical data

Table Of Contents
SFBs for Compact CPUs
System Software for S7-300/400 System and Standard Functions - Volume 2/2
A5E00739858-01
28-51
Declarations in the Message Frame
The table below shows the declarations in the message frame header of the
RK 512 message frame.
Source on your S7
automation system
(local CPU)
To target,
partner CPU
Message frame header, bytes
3/4 Instruction
type
5/6 D-DBNR/D
Offset
7/8 Number in
Data block Data block AD DB/DW Words
Data block Expanded data block AD DB/DW Words
Explanation of the abbreviations used:
D-DBNR Destination data block number
D Offset Destination start address
DW Offset in Words
Data Consistency
Data consistency is limited to 128 bytes. If you want to consistent data
transmission exceeding these 128 bytes, you must take the following into account:
Do not write to the currently used section of the send range SD_1 unless the
transmission has been terminated. This is the case when the state parameter
DONE has the value TRUE.
See also:
Additional Error Information of the SFBs 60 to 65