Siemens SINUMERIK 840D sl Function Manual page 815

Reliability of channel axis gaps
Channel axis gaps must be communicated explicitly through the following machine data:
MD11640 $MN_ENABLE_CHAN_AX_GAP (channel axis gaps are allowed in
AXCONF_MACHAX_USED)
If this is not carried out, an entry of 0 prevents other machine axes being assigned to
channel axes in the following machine data:
MD20070 $MC_AXCONF_MACHAX_USED (machine axis number valid in channel)
References:
/FB2/ Function Manual, Extension Functions; Several Control Panels on Multiple NCUs,
Decentralized Systems (B3)
Example
In the example below, a machine tool channel axis is specified without a real machine axis.
Figure 2-5
Basic logic functions: Axes, coordinate systems, frames (K2)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Axis configuration with channel axis gap
Detailed description
2.1 Axes
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