Siemens SINUMERIK 840D sl Function Manual page 1299

NC tags
The latest NC VAR selector can be used for each NCU software version (even earlier
versions). The variables can also be selected from the latest list for earlier NC software
versions. The data content in DB 120 (default DB for variables) does not depend on the
software version, i.e., selected variables in an older software version must not be reselected
when the software is upgraded.
2.4.8 I/O modules (FM, CP modules)
Special packages for STEP7 are generally required for more complex I/O modules. Some of
these special packages include support blocks (FC, FB) stored in a STEP7 library. The
blocks contain functions for operating the relevant module which are parameterized and
called by the user program. In many cases, the FC numbers for the CP and FM module
handling blocks are also included in the number range of the basic program for the 840D.
What can one do in these conflicts?
The block number of the basic program must remain unchanged. The block numbers of
handling blocks can be assigned new, free numbers using STEP7. These new blocks (with
new FC numbers) are then called in the user program with the parameter assignments
required by the function.
Basic logic functions: PLC basic program solution line (P3 sl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Detailed description
2.4 Starting up the PLC program
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