Siemens SINUMERIK 840D sl Function Manual page 1495

Limit values
The compensation values are restricted to the maximum values by the machine data:
MD20392 $MC_TOOL_TEMP_COMP_LIMIT[0...2] (maximum temperature compensation for
tool length)
The limit value default setting is 1 mm. If a temperature compensation value higher than this
limit is specified, it will be limited without an alarm.
SD42960
The three temperature compensation values together form a compensation vector and are
contained in setting data:
SD42960 $SC_TOOL_TEMP_COMP[0...2] (temperature compensation with reference to
tools)
The setting data is user-defined, e.g. using synchronized actions or from the PLC. The
compensation values can, therefore, also be used for other compensation purposes.
In the initial state or when orientation transformation is deactivated, all three compensation
values apply in the direction of the three geometry axes (in the typical order X, Y, Z). The
assignment of components to geometry axes is independent of the tool type (turning, milling
or grinding tools) and the selected machining plane G17 to G19. Changes to the setting data
values take effect immediately.
Toolholder with orientation capability
If a toolholder with orientation capability is active, the temperature compensation vector is
rotated simultaneously to any change in orientation. This applies independently of any active
orientation transformation.
If a toolholder with orientation capability is active in conjunction with a generic 5-axis
transformation or a transformation with rotating linear axis, the temperature compensation
vector is subjected to both rotations.
Note
While transformations with rotating linear axes take changes in the tool vector (length) into
account, they ignore its change in orientation, which can be effected by a toolholder with
orientation capability.
Temperature compensation values immediately follow any applied change in orientation. This
applies in particular when an orientation transformation is activated or deactivated.
The same is true when the assignment between geometry axes and channel axes is changed.
The temperature compensation value for an axis is reduced to zero (interpolatively), for
example, when it ceases to be a geometry axis after a transformation change. Conversely,
any temperature compensation value for an axis which changes over to geometry axis status
is applied immediately.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
18.10 Special handling of tool compensations
W1: Tool offset
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