Siemens Simantic Net NCM for Industrial Ethernet S7 User Manual

Page 76

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.

ЗЗЗЗЗЗЗЗ

НННННННН

AG_RECV

ННННННННН

AG_SEND

Read in the received
data of the
connection

Transfer send data
for the connection

Write PIQ

ЗЗЗЗЗЗЗЗЗ

Legend:

Sequence of the CPU cycle

AG_RECV

Communication
connection

ЗЗЗЗЗЗЗ

ННННННН

AG_SEND

User program

The different shading shows which
connections and FC blocks belong
together.

ЗЗ

НН

Read PII

Communication
connection

Figure 3-2

Typical Sequence of Function Calls in the CPU Cycle

The following points are illustrated by the diagram:

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).