Switchover Modes For Dryrun And Skip Levels - Siemens Sinumerik 840D sl Programming Manual

Figure 4-25
Main program
N10 G00 G90 X0 Y0
N20 G01 G17 G41 X30. Y0 G43H99 F1000
N30 Y10.
N40 X30.
N50 G72.2 P2000 L3 I80. J0
Subroutine 2000.mpf
G90 G01 X40.
N100 Y30.
N200 G01 X80.
N300 G01 Y10.
N400 X110.
500 M99
4.8.2

Switchover modes for DryRun and skip levels

Changeover of the skip levels (DB21.DBB2) always represents an intervention in the
program run, which has led to a short-term drop in velocity on the path. The same is true of
the changeover of the DryRun mode (DryRun = dry run feedrate DB21.DBB0.BIT6) from
DryRunOff to DryRunOn or vice-versa.
All the drops in velocity can be avoided with a changeover mode that is limited in its function.
No drop in velocity is required with a setting machine data 10706 $MN_SLASH_MASK==2
while changing the skip levels (i.e., a new value in the PLC->NCK-Chan interface
DB21.DBB2).
Note
The NCL processes blocks in two steps, the preprocessing and main runs (also pre-travel
and main run). The result of the premachining changes to the preprocessing memory. The
main machining takes the relevant oldest block out of the preprocessing memory and
traverses its geometry.
ISO Milling
Programming Manual, 06/09, 6FC5398-7BP10-1BA0
Contour repetition with G72.2
Additional functions
4.8 Special functions
137