Siemens SINUMERIK 840D sl Function Manual page 1533

Further explanations
If the tool length components are parallel to the geometry axes, the axis indices assigned to
length components L1 to L3 are returned in the _AXIND array.
If a tool length component points in the negative axis direction, the associated axis index
contains a minus sign. In this case, the return value (status) is 0. If an axis does not exist, the
associated return value is 0. The assignment can also be read from the _MATRIX parameter.
Six of the nine matrix elements are then zero, and three elements contain the value +1 or -1.
Note
In the TCS, all tool length components are always parallel or antiparallel to the axes.
The components can only be antiparallel when mirroring is active and the following setting
data is activated:
SD42900 $SC_MIRROR_TOOL_LENGTH (sign change tool length when mirroring)
If not all length components are parallel or antiparallel to the geometry axes, the index of the
axis, which contains the largest part of a tool length component, is returned in _AXIND. In this
case (if the function does not return an error for a different reason), the return value is 1. The
mapping of tool length components L1 to L3 onto geometry axes 1 to 3 is then described
completely by the contents of the 3rd parameter _MATRIX.
The _COORD parameter can be used to specify, which coordinate system is to be used for
the geometry axes. If the _COORD parameter is not specified (notation LENTOAX(_AXIND,
_MATRIX)), the WCS is used (default).
Example:
Standard situation: milling tool with G17
L1 applies in Z (applicate), L2 applies in Y (ordinate), L3 applies in X (abscissa).
Function call in the form:
Status = LENTOAX(_AXIND, _MATRIX, "WCS")
The result parameter _AXIND contains the values:
_AXIND[0] = 3
_AXIND[1] = 2
_AXIND[2] = 1
Or, in short: ( 3, 2, 1)
In this case, the associated matrix _MATRIX is:
A change from G17 to G18 or G19 does not alter the result, because the assignment of the
length components to the geometry axes changes in the same way as the assignment of the
abscissa, ordinate and applicate.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
18.13 Tool lengths L1, L2, L3 assignment: LENTOAX
W1: Tool offset
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