Siemens SINUMERIK 840D sl Commissioning Manual page 227

Channel axis gaps
Normally, using MD20070, a channel axis is assigned to one machine axis. Not every channel
axis must be assigned to a machine axis. Each channel axis with MD20070 [n] = 0 is not
assigned any machine axis and represents a channel axis gap.
Channel axis gaps allow the creation of a uniform configuration of the channel axes over
different machine versions of a series. Each channel axis of the series has a defined task or
function. If the function and therefore the machine axis is not available on a specific machine,
the relevant channel axis is not assigned a machine axis:
MD20070 $MC_AXCONF_MACHAX_USED[<channel axis>] = 0
Advantages:
● Commissioning archive with uniform basic configuration
● Simple post configuration for the specific machine
● Flexible portability of part programs
Enabling channel axis gaps
The use of channel axis gaps is enabled using the machine data:
MD11640 $MN_ENABLE_CHAN_AX_GAP = 1 (channel axis gap allowed).
If the use of channel axis gaps has not been enabled, then the value 0 for channel axis n in the
following machine data terminates the allocation of additional machine axes to possible
channel axes from channel axis n onwards:
MD20070 $MC_AXCONF_MACHAX_USED[<channel axis n>]
Supplementary conditions:
● Regarding the number of channel axes and the indexing, a channel axis gap counts just the
same as axes.
● Ensure that a geometry axis is not assigned to a channel axis, that is not assigned to a
machine axis (channel axis gap). No alarm is displayed.
● Transformation: When configuring a channel axis in the following machine data, which is not
assigned a machine axis (channel axis gap), an alarm is output:
– MD24110 ff. $MC_TRAFO_AXES_IN1...8
– MD24120 ff. $MC_TRAFO_GEOAX_ASSIGN_TAB1...8
Example
The 5th channel axis "B" in MD20070 is not assigned to a machine axis.
If channel axis gaps are enabled, six machine axes (1 - 4, 5, 6) are available.
If channel axis gaps are not enabled, then there are four machine axes (1 - 4) available.
CNC Commissioning: NC, PLC, Drive
Commissioning Manual, 12/2019, A5E48312804B AA
Communication between the NC and the drive
7.6 Configuring machine axes
227