Siemens SINUMERIK 840D sl Function Manual page 682

V2: Preprocessing
18.1 Brief description
Memory is required for preprocessing cycles. You can optimize your memory in two ways:
• The program to be executed can be shortened with the command DISPLOF (display off).
• MD10700 $MN_PREPROCESSING_LEVEL has been expanded by bit 2 and 3. This
allows selective cycle preprocessing of the individual directories (e.g. user cycles).
MD10700 $MN_PREPROCESSING_LEVEL has been expanded by bit 4. This allows you to
select preprocessing for user cycles from the _N_CMA_DIR directory.
MD10700 $MN_PREPROCESSING_LEVEL has been expanded by bit 5. This allows
selective preprocessing of the specific individual user cycles that have the command PREPRO
after the PROC instruction.
Pretranslated cycles are stored in the dynamic NC memory by default. MD10700
$MN_PREPROCESSING_LEVEL has been expanded by bit 6. This allows specifying that the
compiled programs that are now stored in the dynamic NC memory and no longer have
enough space can be stored in static NC memory.
Functionality
The programs stored in the directories for standard and user cycles are preprocessed when
the power is switched on, i.e. the part program is translated (compiled) into an intermediate
binary code optimized for processing purposes. The compilation is processed when called.
Runtime optimization
The preprocessing function is primarily suited for optimizing the runtimes of part programs
with high-level language components (branches, check structures, motion-synchronous
actions).
While branches and check structures are invalidated by a search through all blocks (block
start) when part programs are interpreted in ASCII format (active as default), a branch is
made directly to the destination block in a preprocessed part program.
The runtime differences between branches and check structures are thus eliminated.
Example of a preprocessing runtime:
Runtime reduction by 30% with active compressor
DEF INT COUNTER
Target: G1 G91 COMPON
G1 X0.001 Y0.001 Z0.001 F100000
COUNTER=COUNTER +1
COUNTER=COUNTER -1
COUNTER=COUNTER +1
IF COUNTER<= 100000 GOTOB TARGET
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Function Manual, 09/2011, 6FC5397-2BP40-2BA0
Special Functions