Siemens SINUMERIK 840D sl Function Manual page 690

Measurement (M5)
Setting zeros, workpiece measuring and tool measuring
Two milling tools with one reference point with a tool orientation in -y
In the case of the tool position of two milling tools with one reference point, not only are the
input variables of measurement type 23 evaluated but also the values of the following input
variables:
Approach direction +x, tool orientation -y
$AC_MEAS_TOOL_MASK = 0x80 + 0x200
$AC_MEAS_DIR_APPROACH = 0
690
Approach direction -x, tool orientation -y
$AC_MEAS_TOOL_MASK = 0x80
$AC_MEAS_DIR_APPROACH = 1
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Extended Functions