7 Programming FCs (Functions) and FBs for S7 Ethernet CPs
A-194
S7-CPs for Industrial Ethernet Configuring and Commissioning
Release 01/2007
C79000-G8976-C182-07
Notice
Please note the following special feature on TCP connections:
With the older S7-CPs for S7-400, you must use FC AG_LSEND on TCP
connections!
With the latest S7-CPs for S7-300, you must also use FC AG_SEND for TCP
connections.
How the Block Works
The following diagrams illustrate the normal sequence of data transmission
triggered in the user program using AG_SEND.
The way in which the FC functions depends on the CP type you are using.
Case a: Sequence with older CP types
With older CP types, the transfer of the entire data area regardless of its length
is started after the first block call by the CP.
Case b: Sequence with newer CP types (S7-300 only!)
With the newer CP types, data transfer has been optimized. In particular with
longer data records, this allows a much higher data throughput on the interface
between the CPU and CP.
FC5 AG_SEND / FC50 AG_LSEND - continued
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