Siemens NCM S7 Manual De Usuario

167

SIMATIC NET NCM S7 for Industrial Ethernet
Release 6/2003

C79000–G8976–C129–07

Before describing the FCs in detail, a few general comments on calling and setting
parameters for FCs will be useful in this point.

It is possible to make the following general statements about the following
parameter groups that occur in all FCs:

S

Parameters for CP and connection assignment (input parameters)

S

Parameters for specifying a CPU data area (input parameters)

S

Status information (output parameters)

The communication blocks for S7-300 (SIMATIC NET block libraries for S7-300 in
STEP 7) must not be called in more than one priority class! If, for example, you
call a communication block in OB1 and in OB35, block execution could be inter-
rupted by the higher-priority OB.

If you call blocks in more than one OB, you must write your program so that a
communication block that is currently executing cannot be interrupted by another
communication block (for example by disabling/enabling SFC interrupts).

When you call an FC, you transfer the module start address of the Ethernet CP in
the CPLADDR or LADDR parameter. The module start address of the Ethernet CP
can be found in the properties dialog of the CP in the ”Address/Input” tab (can be
selected in the SIMATIC Manager or in HW Config).

With connection-oriented jobs, you must also reference the connection to be used
by its connection ID. You will find this in the properties dialog of the connection
under “Block parameters” (refer to the information in NetPro).