Siemens SINUMERIK 840D sl Function Manual page 560

Kinematic Transformation (M1)
Chained transformations
Selection and deselection
Persistent transformation is selected via the following machine data:
MD20144 $MC_TRAFO_MODE_MASK, Bit 0 = 1
MD20144 $MC_TRAFO_RESET_VALUE defines persistent transformation.
MD20140 $MC_TRAFO_RESET_VALUE=Number of the transformation data set of the
persistent transformation
In addition the following must be set (i.e. noted):
MD20110 $MC_RESET_MODE_MASK
Bit 0 = 1 (Bit 7 is evaluated)
Bit 7 =0 (MD20140 $MC_TRAFO_RESET_VALUE determines the transformation data set)
MD20112 $MC_START_MODE_MASK (MD20140 $MC_TRAFO_RESET_VALUE)
MD20118 $MC_GEOAX_CHANGE_RESET= TRUE (i.e. geometry axes are reset).
If this additional data is not parameterized correctly,
alarm 14404 is generated.
With TRAFOOF the active TRACON is deselected and the persistent transformation is
automatically selected.
Effects on HMI operation
As a transformation is always active with the persistent transformation, the HMI user
interface is adapted accordingly for the selection and deselection of transformations:
TRACON on HMI
Accordingly the HMI operator interface does not display TRACON, but the first chain
transformation of TRACON e.g. TRANSMIT . Accordingly, the transformation type of the 1st
chained transformation is returned by the corresponding system variable, i.e. $P_TRAFO
and $AC_TRAFO. Cycles written in TRANSMIT can then be used directly.
TRACOOF on HMI
In accordance with the TRAFOOF programming instruction no transformation is displayed in
the G code list on the HMI user interface. System variables $P_TRAFO and $AC_TRAFO
therefore return a value of 0, the persistent transformation is operative and the BCS and
MCS coordinate systems do not coincide. The displayed MCS position always refers to the
actual machine axes.
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Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Extended Functions