S5-115F Manual
Communications Capabilities
Indirect assignment of FB 252 parameters
If you want to assign the FB 252 parameters indirectly, you must store the data for assigning the
block parameters in a DB. For this purpose, write the parameter assignments in six consecutive
data words. You must note the order of the parameters!
You must specify the following when calling FB 252:
•
The value ”XX” for the TYP parameter
•
The number of the DB (DB 4 to 255) with the block parameter assignments for the DBNR
parameter
or
the value ”C” for the DBNR parameter if the last opened DB contains the block parameter
assignments
•
The number of the data word containing the first block parameter (BADR parameter) for the
ANFA parameter.
The BADR, FUNK and BLCK parameters must be assigned permissible values but the values them-
selves are insignificant in this case.
Sending and receiving data in communications mode
Data transfer must be coordinated before you can send a message frame to the CP 523. For this
reason, message frame transfer can be divided into three steps.
1st step
The CPU transfers the ”Send message” or ”Receive message” job request to the CP 523. The CP
reads the job request from its transfer memory and writes transfer information autonomously into
the transfer memory.
2nd step
The CPU reads the coordination information from the transfer memory and evaluates it. The
actual message can be sent or received when the CP 523 has accepted the job.
3rd step
The CPU sends or receives the message of up 32 eight-byte data blocks.
To make the user program as clear as possible, FB 252 BLUE should be called with the relevant
function for each of the above steps.
Note
Function blocks FB 200 and FB 201 described in the CP 523 Manual cannot be used in
the S5-115F.
The following flowchart shows data transfer with three FB 252 BLU calls for the ”Send message”
job.
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