Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
158
Manual, 09/2008, A5E02191071-01
Parameters in the FB for data source (Partner CPU)
The following table lists the data types that can be transmitted.
Table 6- 9
Transmittable data types for "Fetch data" request
Source on the partner
CPU
R_TYP
R_NO
R_OFFSET (in bytes)
(This value is specified by the partner CPU.)
Data block
'D'
0 - 255
0 - 510
(only even-numbered values are appropriate!)
Expanded data block
'X'
0 - 255
0 - 510
(only even-numbered values are appropriate!)
Bit memory
'M'
irrelevant
0 - 255
Inputs
'I'
irrelevant
0 - 255
Outputs
'Q'
irrelevant
0 - 255
Counters
'C'
irrelevant
0 - 255
Timers
'T'
irrelevant
0 - 255
Information in the message frame header
The table below shows the information in the message frame header of the RK 512 message
frame.
Table 6- 10 Information in the RK 512 message frame header for "Fetch data" request
Source on the partner CPU To the destination, your S7
automation system (local
CPU)
Message frame header, bytes
3/4 command type
5/6 S-DBNR/S-
offset
7/8 number in
Data block
Data block
ED
DB/DW
Words
Expanded data block
Data block
EX
DB/DW
Words
Bit memory
Data block
EM
Byte address
Bytes
Inputs
Data block
EE
Byte address
Bytes
Outputs
Data block
EA
Byte address
Bytes
Counters
Data block
EC
Counter no.
Words
Timers
Data block
ET
Timer number
Words
Explanation of the abbreviations used:
S-DBNR: Source data block number
S-Offset: Source start address
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