Siemens SINUMERIK 840Di Function Manual page 1004

Detailed description
2.12 Block descriptions
2.12 Block descriptions
2.12
2.12.1 FB 1: RUN_UP Basic program, startup section
Description of Functions
The synchronization of NCK and PLC is performed during startup. The data blocks for the
NC/PLC user interface are created with reference to the NC configuration defined in the
machine data and the most important parameters verified for plausibility. In the event of an
error, FB 1 passes an error identifier to the diagnostics buffer and switches the PLC to the
STOP state.
To enable an orderly startup of the control, it is vital to synchronize the NCK and PLC, as
these systems have their own types of powerup procedure. During startup routine, therefore,
the CPUs perform "subsidiary startup functions" and exchange ID information to ensure that
the procedure is functioning correctly.
Since the startup procedure is asynchronous, it is unavoidable that one CPU may have to
"wait" until the other has "caught up". This is automatically managed by the basic program.
The PLC 314 and PLC 315-2DP only know the start-up type cold restart. A warm restart is
not provided, i.e., following system initialization, the operating system runs organization
block OB 100 and always commences cyclic execution at the start of
OB 1.
Users need only supply the FB 1 parameters that are relevant to their applications. The
preset values in the associated instance DB 7 do not need to be assigned. The block can
only be called in OB 100.
Output parameters
The output parameters in FB 1 provide the PLC user with information about the control
system configuration. These data can also be accessed in the cyclic program section.
There are two access options:
1. Direct access to the DB 7 data block (instance of the FB 1) in symbolic format (e.g., L
2. Assignment of a flag; during parameterization of the FB 1, the data element is assigned
2-92
gp_par.MaxChan; in this case, gp_par is the symbolic name of the DB 7)
to the relevant parameter (e.g., MaxChan:=MW 20) Information about the maximum
number of channels can then be polled in memory word 20 in the rest of the user
program.
Note
An additional SDB 210 must be generated via the STEP7 Communication Configuration
application for the operator components connected on the MPI interface.
The corresponding procedure is explained in the Installation and Startup Guide.
Power Line Basic PLC Program (P3)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0