Temporal Conditions Concerning Nc Start; Block Search From Last Main Block - Siemens SINUMERIK 840D sl Function Manual

TE7: Continue machining - retrace support
15.6 Retrace support
Channel axes
All other channel axes programmed in the part program travel to the relevant position
calculated in the block search.
15.6.4

Temporal conditions concerning NC start

NC start should be initiated twice by the machine operator within the framework of continue
machining (refer to Functional sequence (principle) [Page 614]).
The following conditions must be met:
• In NC start for outputting the action blocks:
-
• In NC start for outputting the approach blocks:
-
15.6.5

Block search from last main block

The block search with calculation on the contour executed within the framework of the
machining continuation via the use of the most powerful NCU in very large part programs can
itself lead to computation times of several minutes up to the reaching of the target block.
A significant reduction of this waiting period is possible through the use of the "Block search
from the last main block".
Functionality
For retrace support with block search from the last main block, the search for the target block
takes place in 2 stages:
1. Block search without calculation from start of machining program to last main block before
target block. Subroutines are ignored during this search, i.e. it takes place exclusively in
the main program.
2. Block search with calculation on contour from main block to target block. This block search
does not ignore subroutines.
Requirement
To enable a search from last main block for retrace support, at least one main block must be
programmed after the RESU start CC_PREPRE(1).
636
The block search must be completed:
DB21, ... DBX33.4 = 0 (block search active)
The RESU ASUB "CC_RESU_BS_ASUP" must be completed:
DB21, ... DBX318.0 = 1 (ASUB stopped)
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
Special Functions