Programming The Send/Receive Interface - Siemens S7-300 Configuration Manual

4.2

Programming the SEND/RECEIVE interface

Principle of job and data transfer
With the program block calls, the user program initiates the transfer of the user data areas
and monitors execution of the transfer by evaluating the condition codes of the FCs.
Among other things, the following parameters are transferred during the call:
● The connection number of the connection (ID);
● The location of the user data area on the CPU.
Task of the program blocks
Calling the program blocks brings about the following action:
● The user data area is transferred to the Ethernet CP or is accepted from the Ethernet CP.
● The execution of the job is only confirmed in the positive or negative status.
Follow the steps below
Program the SEND/RECEIVE interface in the user program as follows:
1. Use the following program blocks for data transfer with connections:
2. Evaluate the condition codes of the program blocks:
Configuring and commissioning S7 CPs for Industrial Ethernet
Configuration Manual, 09/2013, C79000-G8976-C182-13
– AG_SEND / AG_LSEND / AG_SSEND for transferring the user data area to the
Ethernet CP;
– AG_RECV / AG_LRECV / AG_SRECV for adopting the data received from the
Ethernet CP in the user data area;
– With AG_SEND / AG_LSEND / AG_SSEND, the parameters DONE, ERROR,
STATUS;
– With AG_RECV / AG_LRECV / AG_SRECV, the parameters NDR, ERROR, STATUS;
Note
Connection numbers (IDs) must be adopted in the programming from the
configuration.
To ensure correct parameter assignment for the block calls, STEP 7 provides the
option of adopting relevant parameters from the CP configuration automatically in the
LAD/STL/FBD editor. For more detailed information, refer to the online help in STEP
7.
SEND/RECEIVE interface in the user program
4.2 Programming the SEND/RECEIVE interface
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