Technical data

SFBs for Compact CPUs
System Software for S7-300/400 System and Standard Functions - Volume 2/2
28-60 A5E00739858-01
Example: SEND_RK with connection memory bit
In this example the communication partner transmits data to DB 101 on your CPU
1. In your CPU, set the connection memory bit 100.6 to FALSE.
9. In your communication partner, specify connection memory bit 100.6
(parameters R_CF_BYT, R_CF_BIT) for the SEND job.
The connection memory bit is transferred to your CPU in the RK 512 message
frame header.
Before it processes the job, the CPU verifies the connection memory bit that is
specified in the RK512 message frame header. Th job is only processed if the
connection memory bit is set to FALSE value on your CPU. If the connection
memory bit is set to TRUE the error message "32 hex" is transmitted in the
response message frame to the communication partner.
After the data are transferred to the DB101 connection memory 100.6 is set to
TRUE on your CPU by SFB SERVE. Also, the connection memory byte and bit
is output on SFB SERVE for the duration of one call (if NDR =TRUE).
10. When you evaluate the connection memory (connection memory 100.6 =TRUE)
in your user program you can see whether the job is completed and the
transmitted data can be processed.
11. After you have processed the data in your user program you must reset the
connection memory 100.6 to FALSE. Not until the can your partner execute the
job again without error.