Technical data

Copy and Block Functions
System Software for S7-300/400 System and Standard Functions - Volume 1/2
3-16 A5E00709327-01
3.9 Generating Data Blocks in Load Memory with SFC 82
"CREA_DBL"
Description
With SFC 82 "CREA_DBL" (create data block in load memory) you can create a
new data block in the load memory (Micro Memory Card). The SFC 82 generates a
default size data block using a number from a specified range and. The SFC 82
assigns the smallest possible number to the DB. You can generate a DB with a
certain number by assigning the same number to the upper and to the lower limit of
the rage to be specified. You cannot assign numbers that are already assigned to
DBs that exist in the user program. If a DB already exists with the same number in
work memory and/or load memory or if the DB exists as copied version the SFC is
terminated and an error message is generated.
Note
With the SFC 24 "TEST_DB" you can determine whether a DB with the same
number already exists.
The content of the data area to which the parameter SRCBLK (source block) points
are written to the DB. This data area must be a DB or an area from a DB. To
maintain consistency, you must not change this data area while the SFC 82 is
being processed (i.e. as long as the BUSY parameter has the value TRUE).
A DB with READ_ONLY attribute can only be created and initialized by SFC 82.
The SFC 82 does not change the checksum of the user program.