Siemens SINUMERIK 840D sl Function Manual page 87

Axis is already assigned to the requested channel
If the requested axis has already been assigned to this channel at the point of activation, and
its status is that of a neutral axis not controlled by the PLC $AA_AXCHANGE_TYP[axis]==3,
it is assigned to the NC program $AA_AXCHANGE_TYP[axis]==0.
This results in a reorganization procedure.
Axis in the state of the neutral axis is controlled from the PLC
If the axis in neutral axis state is controlled by the PLC $AA_AXCHANGE_TYP[axis]==4), the
axis is requested as a neutral axis $AA_AXCHANGE_TYP[axis] == 8. This disables the axis
for automatic axis replacement between channels (Bit 0 == 0) in accordance with the value of
bit 0 in machine data:
MD10722 $MN_AXCHANGE_MASK (parameterization of the axis replacement behavior)
This corresponds to $AA_AXCHANGE_STAT[axis] == 1.
Axis is active as command axis / assigned to the PLC
If the axis is active as a command axis or oscillating axis or a concurrent positioning axis (PLC
axis) ($AA_AXCHANGE_TYP[<axis>] == 1), the axis is requested as a neutral axis
($AA_AXCHANGE_TYP[<axis>] == 8). Depending on the setting in the following machine data,
the axis is blocked for an automatic axis replacement between channels:
MD10722 $MN_AXCHANGE_MASK (parameterization of the axis replacement behavior)
This corresponds to $AA_AXCHANGE_STAT[<axis>] == 1.
With a further GET request, the axis is then requested for the NC program ⇒
$AA_AXCHANGE_TYP[axis] == 7.
Axis already assigned to the NC program of the channel
If the axis is already assigned to the NC program of the channel
($AA_AXCHANGE_TYP[<axis>] == 0) or if this assignment is requested, e.g. axis replacement
triggered by the NC program ($AA_AXCHANGE_TYP[<axis>] == 5 or
$AA_AXCHANGE_TYP[<axis>] == 7), there is no state change.
Release axis for axis replacement
If the axis is assigned to the NC program at the time of release ($AA_AXCHANGE_TYP[<axis>]
== 0), it is transferred to the neutral axis state ($AA_AXCHANGE_TYP[<axis>] == 3) and if
required, released for axis replacement in another channel.
This results in a reorganization procedure.
Axis to be released is already a neutral axis:
If the axis is already in the neutral axis state ($AA_AXCHANGE_TYP[<axis>] == 3) or active
as command or oscillating axis or assigned to the PLC as concurrent positioning axis
($AA_AXCHANGE_TYP[<axis>] == 1), the axis is released for an automatic axis replacement
between channels.
Synchronized actions
Function Manual, 08/2018, 6FC5397-5BP40-6BA2
Detailed description
3.7 Actions in synchronized actions
87