Additive Offsets - Siemens SINUMERIK 840D sl Function Manual

K2: Axis Types, Coordinate Systems, Frames
10.4 Coordinate systems
10.4.4

Additive offsets

External work offsets
The external work offset is a linear offset between the basic coordinate system (BCS) and the
basic zero system (BZS).
The external work offset $AA_ETRANS is effective in two ways depending on the machine
data parameterization:
1. The $AA_ETRANS system variable has a direct effect as offset value after activation by
the NC/PLC interface signal.
2. The value of the $AA_ETRANS system variable is taken into the system frame
$P:EXTFRAME and the data management frame $P_EXTFR after activation by the NC/
PLC interface signal. The active complete frame $P_ACTFRAME is then recalculated.
Machine data
In conjunction with the $AA_ETRANS system variable, a distinction is made between two
procedures which are selected via the following machine data:
MD28082 $MC_MM_SYSTEM_FRAME_MASK, bit1 = <value>
<value> Meaning
0 Function: Direct writing of $AA_ETRANS[<axis>] by the PLC, HMI or NC program.
Enable to traverse the work offset of $AA_ETRANS[<axis>] in the next possible traversing block: DB31, ...
DBX3.0
1 Function: Activation of the active system frame $P:EXTFRAME and the data management frame $P_EXTFR
Enable to traverse the work offset of $AA_ETRANS[<axis>] through: DB31, ... DBX3.0. Then in the channel:
● Stop of all traversing movements in the channel (except command and PLC axes)
● Preprocessing stop with subsequent reorganization (STOPRE)
● Coarse offset of the active frame $P_EXTFRAME[<axis>] = $AA_ETRANS[<axis>]
● Coarse offset of the data management frame $P_EXTFR[<axis>] = $AA_ETRANS[<axis>]
● Recalculation of the active complete frame $P_ACTFRAME
● Traversing of the offset in the programmed axes.
● Continuation of the interrupted traversing movement or the NC program
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Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions