Siemens SINUMERIK 840Di Function Manual page 760

Detailed Description
2.3 Coordinate systems
Overlaid movements
The "Superimposed motion" for the programmed axis can only be accessed from
synchronized actions via the system variable $AA_OFF[axis].
Run-up
After run-up (POWER ON), the last used offset values for the "Zero offset external" are
stored and do not become effective again until there is a renewed activation signal.
Depending on the machine data
MD24008 CHSFRAME_POWERON_MASK,
system frames are retained on POWER ON.
RESET/end of program
The activated values remain active after RESET and program end.
Reset response of the channel-specific system frames is as follows:
With machine data setting
MD24006 CHSFRAME_RESET_MASK, Bit 1 = 1,
the system frame for the "Zero offset external" becomes active following RESET.
With machine data setting
MD24006 CHSFRAME_RESET_MASK, Bit 1 = 0,
the "Zero offset external" in the active system frame is deleted in the data management.
Following RESET, these frames are active:
System frame for
MD24006 CHSFRAME_RESET_MASK, Bit 4 = 1 (workpiece reference points)
MD24006 CHSFRAME_RESET_MASK, Bit 5 = 1 (cycles)
Suppression
The NC program instruction SUPA suppresses the "Zero offset external" while the block is
being processed.
The command G74 (reference point approach) and the equivalent operator actions in
"Reference point approach" mode suppress the "Zero offset external" for the duration of the
reference point approach.
With G74, i.e., "Automatic" or "MDA" mode, the previously active "Zero offset external"
automatically becomes active again with the next traverse motion in the block.
After a mode change from "Reference point approach" mode, the VDI signal for the
referenced axes must be set for reactivation.
2-30
Axis Types, Coordinate Systems, Frames (K2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0