Siemens SINUMERIK 840D sl Function Manual page 493

Figure 7-3
MD24920 $MC_TRANSMIT_BASE_TOOL_t[0]=tx
MD24920 $MC_TRANSMIT_BASE_TOOL_t [1]=ty
MD24920 $MC_TRANSMIT_BASE_TOOL_t [2]=tz
In this case, "t" in front of the index specification [ ] is substituted by the number of the
TRANSMIT transformations declared in the transformation data blocks (t may not be greater
than 2).
Replaceable geometry axes
The PLC is informed when a geometry axis has been replaced using GEOAX( ) through the
optional output of an M code that can be set in machine data.
● MD22534 $MC_TRAFO_CHANGE_M_CODE
References:
/FB1/ Function Manual, Basic Functions; K2, "Coordinate Systems, Axis Types, Axis
Configurations, Workpiece-related Actual-Value System, External Zero Offset"
Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Position of tool zero in relation to origin of the Cartesian coordinate system
Number of the M code that is output at the VDI interface in the case of transformation
changeover.
Note
If this machine data is set to one of the values 0 to 6, 17, 30, then no M code is output.
Kinematic Transformation (M1)
7.2 TRANSMIT
493