Siemens SINUMERIK 840D sl Function Manual page 848

Detailed description
2.4 Frames
2.4.3.3 NCU global frames
All settable frames G54 to G599 and all basic frames can be configured NCU globally or
channel-specifically. A combination of these is also possible with basic frames. Global
frames affect all channels on an NCU. All channels have read and write access to the NCU.
Global frames only have axial frame components, such as translations, scales and mirrors of
individual axes. Each channel can read or modify global frames for any machine axis.
A characteristic of global frames is that they are calculated in all channels of an NCU. As the
assignment of machine axes to channel axes and, in particular, to geometry axes, can be
different in all channels, there is no geometric relationship. Global frames describe offsets,
scales and mirrors of machine axes. Rotations cannot be used on global frames.
All settable frames can be reconfigured to global frames with the following machine data:
MD18601 $MN_MM_NUM_GLOBAL_USER_FRAMES (number of global, pre-defined user
frames (SRAM))
If the value of this machine data is greater than zero, there are no channel-specific settable
frames.
The following machine data becomes irrelevant then, and is not evaluated:
MD28080 $MC_MM_NUM_USER_FRAMES (number of settable frames (SRAM))
The number of global basic frames is parameterized through the following machine data:
MD18602 $MN_MM_NUM_GLOBAL_BASE_FRAMES (number of global, basic frames
(SRAM))
Channel-specific basic frames can also exist simultaneously through the following machine
data:
MD28081 $MC_MM_NUM_BASE_FRAMES (number of basic frames (SRAM))
Global frames can be read and written from all channels of an NCU. When writing global
frames, the user must ensure channel coordination. This can be achieved through e.g., wait
markers.
2.4.4 Frame chain and coordinate systems
2.4.4.1 Overview
The figure below shows the frame chain for the current complete frame. The frame chain is
stored between the BCS and WCS. The SZS (Settable Zero System) corresponds to the
WCS, transformed by the programmable frame. The BZS (Basic Zero System) still includes
the current settable frame. The system frame for the zero offset external is only available if it
has been configured, otherwise the zero offset external is interpolated as a superimposed
motion of the axis, as it has been up to this point.
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Basic logic functions: Axes, coordinate systems, frames (K2)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0