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SEND/RECEIVE Interface in the User Program

SIMATIC NET NCM S7 for Industrial Ethernet

C79000-G8976-C129–06

Calling FCs in the CPU Program

One possible sequence for FCs in conjunction with the organization and program

blocks in the CPU cycle is illustrated in the following diagram.

AG_RECV

AG_SEND

Read in the received

data of the

connection

Transfer send data

for the connection

Write PIQ

Legend:

Sequence of the CPU cycle

AG_RECV

Communication

connection

AG_SEND

User program

The different shading shows which

connections and FC blocks belong

together.

Read PII

Communication

connection

Communication

connection

Figure 3-2 Typical Sequence of Function Calls in the CPU Cycle

The following points are illustrated by the diagram:

S The user program consisting of any number of blocks (OBs, FBs or FCs –> see

also /6/ accesses several connections (Figure 3-2 illustrates three

connections).

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Siemens S7 Manual de usuario Pagina 76