Siemens SINUMERIK 840D sl Function Manual page 800

P2: Positioning axes
11.7 Control by the PLC
● Bit 6 = 1
● Bit 7= 1
For a PLC-controlled axis:
● The channel-specific NC/PLC interface signal DB21, ... DBX6.0 ("feed disable"), is active
● The channel-specific NC/PLC interface signal DB21, ... DBX36.3 ("all axes stationary") is
If an attempt is made to assign an exclusively PLC-controlled axis to the NC program or to
request the axis for the NC program, then this is rejected with Alarm 26075. Alarm 26076 is
generated in the same way for a PLC axis with fixed assignment.
A PLC axis with fixed assignment is a "neutral axis" on power up. For a travel request via the
NC/PLC interface, a concurrent positioning axis automatically changes to a PLC axis without
being interchanged beforehand.
Axis replacement via PLC
The type of an axis for axis replacement is transferred to the PLC with axial interface byte
NCK→PLC NST DB31, ... DBB68:
● IS DB31, ... DBX68.0-68.3 ("NC axis/spindle in channel") channels 1 to 10
● IS DB31, ... DBX68.4 ("new type requested by PLC")
● IS DB31, ... DBX68.5 ("axis can be replaced")
● IS DB31, ... DBX68.6 ("neutral axis/spindle")
● IS DB31, ... DBX68.7 ("PLC axis/spindle")
If IS DB31, ... DBX68.5 ("axis can be replaced") == 1, an axis replacement request can be
issued from the PLC.
References:
Function Manual, Extended Functions; Mode Groups, Channels, Axis Replacement (K5)
800
The channel-specific NC/PLC interface signal:
DB21, ... DBX6.0 ("feed disable")
is not active for the axis if this is a PLC-controlled axis.
The channel-specific NC/PLC interface signal:
DB21, ... DBX36.3 ("all axes stationary")
is set independently of an axis if this is a PLC-controlled axis.
if bit 6 = 0 in machine data MD30460 $MA_BASE_FUNCTION_MASK.
only set if bit 7 = 0 in machine data MD30460 $MA_BASE_FUNCTION_MASK.
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Extended Functions