Siemens SINUMERIK 828D Programming Manual page 401

Further information
Distinguishing features
The most important distinguishing features are shown in the following table:
G code
TOWSTD
TOWMCS
TOWWCS
TOWBCS
TOWTCS
TOWWCS
Linear transformation
The tool length can be defined meaningfully in the MCS only if the MCS is generated by
linear transformation from the BCS.
Non-linear transformation
For example, if with TRANSMIT a non-linear transformation is active, then when specifying
the MCS as requested coordinate system, BCS is automatically used.
No kinematic transformation and no orientable toolholder
If neither a kinematic transformation nor an orientable toolholder is active, then all the other
four coordinate systems (except for the WCS) are combined. It is then only the WCS, which
is different to the other systems. Since only tool lengths need to be evaluated, translations
between the coordinate systems are irrelevant.
References:
For more information on tool compensation, see:
Function Manual Basic Functions; Tool Offset (W1)
Job planning
Programming Manual, 07/2010, 6FC5398-2BP40-0BA0
Wear value
Initial value, tool length
Wear value in MCS.
if a tool holder that can be
TOWSTD
orientated is not active.
The wear value is converted to the MCS in
the WCS.
The wear value is converted to the MCS in
the BCS.
The wear value is converted to the MCS in
the workpiece coordinate system.
, , : The wear vector is added to the tool vector.
TOWBCS TOWTCS
Active orientable toolholder
Wear values are subject to rotation.
is identical to It only rotates the vector of the resultant
TOWMCS
tool length without taking into account the
wear.
The tool vector is calculated as for
without taking into account the wear.
The tool vector is calculated as for
without taking into account the wear.
The tool vector is calculated as for
without taking into account the wear.
7.3 Special handling of tool offsets
Tool offsets
TOWMCS
TOWMCS
TOWMCS
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