7 Programming FCs (Functions) and FBs for S7 Ethernet CPs
A-188
S7-CPs for Industrial Ethernet Configuring and Commissioning
Release 01/2007
C79000-G8976-C182-07
7.3 FCs for the SEND/RECEIVE Interface
Overview
The following FCs are available for transferring data on the SEND/RECEIVE
interface:
FC
Can be used with
1)
Meaning
S7 - 300 S7 - 400
AG_SEND (FC5) x x for sending data
AG_RECV (FC6) x x for receiving data
AG_LSEND (FC50) x for sending data
AG_LRECV (FC60) x for receiving data
1)
Notes on the FCs for an S7-300 and S7-400
S7-300:
With older versions of the Ethernet CPs, the data length per job is restricted to
<=240 bytes (applies up to block version V3.0 of AG_SEND / AG_RECV).
With the latest versions of the Ethernet CPs, only FCs AG_SEND and
AG_RECV are used; due to a new and more efficient internal protocol, the data
up to 8192 bytes can be transferred.
S7-400:
With FCs AG_SEND / AG_RECV the data length per job is restricted to <=240
bytes.
Longer data records (up to 8192 bytes) can be transferred with FCs
AG_LSEND or AG_LRECV.
Please check the supported data area in the device-specific Part B of this manual
for the S7-CP you are using. You will find an overview of the versions of the
FCs/FBs in the documentation and block history.
Application
The following diagram illustrates the use of the FCs described here for
bi-directional data transfer on one configured connection.
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