Siemens SINUMERIK 840D sl Programming Manual page 85

Further syntax rules
• The tool length can be changed simultaneously in all three components. However,
commands of the TOFFL/TOFFL[1..3] group and commands of the TOFF[<geometry
axis>] may not be used simultaneously in one block.
TOFFL and TOFFL[1] may also not be written simultaneously in one block.
• If all three tool length components are not programmed in a block, the components not
programmed remain unchanged. In this way, it is possible to build up offsets for several
components block-by-block. However, this only applies as long as the tool components
have been modified either only with TOFFL or only with TOFF. Changing the programming
type from TOFFL to TOFF or vice versa deletes any previously programmed tool length
offsets (see example 3).
Supplementary conditions
• Evaluation of setting data
The following setting data is evaluated when assigning the programmed offset values to
the tool length components:
SD42940 $SC_TOOL_LENGTH_CONST (change of tool length components on change of
planes).
SD42950 $SC_TOOL_LENGTH_TYPE (assignment of the tool length compensation
independent of tool type)
If this setting data has valid values not equal to 0, then these take preference over the
contents of G code group 6 (plane selection G17 - G19) or the tool type
($TC_DP1[<T no.>, <D no.>]) contained in the tool data, i.e. this setting data influences
the evaluation of the offsets in the same way as the tool length components L1 to L3.
• Tool change
All offset values are retained during a tool change (cutting edge change), e.g. they are
also effective for the new tool (new cutting edge).
Examples
Example 1: Positive tool length offset
The active tool is a drill with length L1 = 100 mm.
The active plane is G17, i.e. the drill points in the Z direction.
The effective drill length is to be increased by 1 mm. The following variants are available for
the programming of this tool length offset:
TOFFL=1
or
TOFFL[1]=1
or
TOFF[Z]=1
Fundamentals
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
5.8 Programmable tool offset (TOFFL, TOFF, TOFFR)
Tool offsets
85