Siemens SIMATIC S5 CP 523 Manual page 172

CP 523
END
EWA 4NEB 811 6044-02a
START
No
Permission to
send?
End-of-
Yes
text character
flag set?
Prepare to transfer message block
DW=end-of-
text character?
Transfer word to CP
Last word of the
message block?
Prepare transfer of next word
Figure 7-11. Flowchart for FB 123 "SEND 3"
Yes
No
Yes
Set end-of-
No
text character
flag
Yes
No
Communications Mode
7-67