Siemens SINUMERIK Series Function Manual page 513

Settings in the system data:
Left-hand tool: Approach direction and tool orientation +x
System variable
$AC_MEAS_TOOL_MASK = 0x2
$AC_MEAS_DIR_APPROACH = 0
Right-hand tool: Approach direction and tool orientation -x
$AC_MEAS_TOOL_MASK = 0x40 + 0x200
$AC_MEAS_DIR_APPROACH = 1
For both tools
$AC_MEAS_Px_COORD = 1
$AC_MEAS_SET_COORD = 1
Extended Functions
Function Manual, 03/2013, 6FC5397-1BP40-3BA1
7.5 Setting zeros, workpiece measuring and tool measuring
Meaning
Tool position in x direction (G19)
Approach direction +x
Tool position in x direction +
Tool length differential values are included
negatively
Approach direction -x
Coordinate system of x-th measuring point = BCS
Coordinate system of the setpoint = BCS
M5: Measurement
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