Siemens sinumerik 840D sl Function Manual page 831

Detailed description
2.2 Program handling
Note
Program changes to precompiled programs do not take effect until the next POWER ON.
Access rights
The preprocessed program can only be executed, but not read or written. The compilation
cannot be modified or archived. The original cycles _SPF files are not deleted.
The compilation is not changed when the ASCII cycle is altered, i.e. changes do not take
effect until after the next POWER ON.
Memory requirements
The memory requirement for compiled cycles is approximately factor 2 in addition to the
ASCII part program.
The memory requirements for variables defined in the part programs are defined by the
following machine data:
MD28020 $MC_MM_NUM_LUD_NAMES_TOTAL (number of local user variables)
MD28010 $MC_MM_NUM_REORG_LUD_MODULES (number of modules for local user
variables with REORG)
MD28040 $MC_MM_LUD_VALUES_MEM (memory size for local user variables)
MD18242 $MC_MM_MAX_SIZE_OF_LUD_VALUE (memory block size for LUD/GUD values)
References:
/FB2/ Function Manual for Extended Functions; Memory Configuration (S7)
While preprocessing is in progress, the amount of memory required is the same as if the
preprocessed program were called on the first subroutine level.
When programs are preprocessed after POWER ON, a name is counted for each branch
destination/label as if it were a variable. These names must be taken into account in the
following machine data:
MD28020 $MC_MM_NUM_LUD_NAMES_TOTAL (number of local user variables)
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Special functions: Preprocessing (V2)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0