Communications Capabilities
S5-115F Manual
Figure 7-21. Flowchart for Sending a Message to the CP 523
END
no
yes
START
Has the CP 523
accepted the job?
FB 252: Send function
CPU transfers the ”Send message” job request
from a memory area of the CPU (flag area or
data block) to the I/O address of the CP 523
CP 523 reads the job and writes the
coordination information into the transfer
memory
FB 252: Receive function*
CPU reads the coordination information from
the I/O address specified by the CP 523 in the
transfer memory
CPU evaluates the received coordination
information
FB 252: Send function
CPU sends the message from the memory area
to the I/O address specified
CP 523 transfers the data received
autonomously from the Send mailbox to the
peripheral device
* You can also read the coordination information with the L PW operation
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