Siemens SINUMERIK 828D Function Manual page 506

K1: Mode group, channel, program operation, reset response
9.7 Block search
Interface signals
In the PLC, the following interface signals are set according to the time sequence shown in the figure:
DB21, ... DBX33.4 (block search active)
DB21, ... DBX32.3 (action block active)
DB21, ... DBX32.4 (approach block active)
DB21, ... DBX32.6 (last action block active)
DB21, ... DBX1.6 (PLC action complete)
Continuation mode after block search
Following the block search, the program can be resumed via interface signal:
DB21, ... DBX7.1 (NC Start).
If an axis is first programmed after "Block search with calculation at block end point", the incremental value can
be added to the value accumulated up to the search target using setting data
SD42444 $SC_TARGET_BLOCK_INCR_PROG.
Action blocks
Action blocks contain the actions accumulated during "Block search with calculation", such as auxiliary function
outputs and tool (T, D), spindle (S), and feedrate programming commands. During "block search with calculation"
(contour or block end point), actions such as M function outputs are accumulated in so­called action blocks.
These blocks are output on an NC Start after "Search target found".
Note
With the action blocks, the accumulated spindle programming (S value, M3/M4/M5/M19,
SPOS) also becomes active.
The PLC user program must ensure that the tool can be operated and that, if necessary, the
spindle programming is reset via PLC signal:
DB31, ... DBX2.2(spindle reset)
or the spindle programming is not output.
Single-block processing: MD10702 $MN_IGNORE_SINGLEBLOCK_MASK ()
By setting bit 3 = 1, it is possible to prevent a stop after every action block in single­block mode.
Boundary conditions for approach block/target block
Block search type 2
Interface signal:
DB21, ... DBX32.4 (approach block active)
is only set with "Block search with calculation at contour" because a separate approach block is not generated
with "Block search with calculation at block end point" (the approach block is the same as the target block).
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Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Basic Functions