Siemens SINUMERIK 840D sl Function Manual page 1009

Compatibility with STEP 7
No interdependencies exist between the basic program (including older program versions)
and currently valid versions of STEP 7.
2.4.3 Version codes
Basic program
The version of the basic program is displayed on the version screen of the HMI software
along with the controller type.
User Program
The user can define his/her own version code for the PLC user program in any data block in
the form of a data string containing a maximum of 54 characters. The data can contain a text
of the user's choice. Parameter assignments for this string are made via a pointer in FB 1.
Parameterization requires symbolic definition of the data block.
References::
/FB1/ Function Manual, Basic Functions; PLC – Basic Program (P3);
Chapter: Block Description
2.4.4 Machine program
The machine manufacturer creates the machine program using the library routines supplied
with the basic program. The machine program contains the logic operations and sequences
on the machine. The interface signals to the NC are also controlled in this program. More
complex communication functions with the NC (e.g., read/write NC data, tool-management
acknowledgments, etc., are activated and executed via basic-program FCs and FBs). The
machine program can be created in different creation languages (e.g., STL, LAD, CSF, S7
HIGRAPH, S7GRAPH, SCL). The complete machine program must be generated and
compiled in the correct sequence. This means that blocks that are called by other blocks
must generally be compiled before the blocks, which call them. If blocks that are called by
other blocks are subsequently modified in the interface (VAR_INPUT, VAR_OUTPUT,
VAR_IN_OUT, VAR) as the program is developed, then the call block and all blocks
associated with it must be recompiled. This general procedure applies analogously to
instance data blocks for FBs. If this sequence of operations is not observed, timestamp
conflicts occur when the data are retranslated into STEP7. In some cases, therefore, it may
not be possible to recompile blocks, creating problems, for example, with the "Block status"
function. It is moreover advisable to generate blocks in ASCIISTL by means of the STEP7
editor when they have been created in the ladder diagram or in single statements
(incremental mode).
Basic logic functions: PLC Basic program powerline (P3 pl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Detailed description
2.4 Starting up the PLC program
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