Siemens SINUMERIK 840D sl Function Manual page 447

$AA_ITR[ <axis>, <transformer layer> ]
The $AA_ITR[ax,n] variable determines the setpoint position of an axis at the output of the nth
chained transformation.
Figure 7-14 Transformer layer
Transformer layer
The 2nd index of the variable corresponds to the transformer layer in which the positions are
tapped:
● Transformer layer 0: The positions correspond to the BCS positions, i.e.:
$AA_ITR[x,0] == $AA_IB[x]
● Transformer layer 1: Setpoint positions at output of 1st transformation
● Transformer layer 2: Setpoint positions at output of 2nd transformation
● Transformer layer 3: Setpoint positions at output of 3rd transformation
● Transformer layer 4: Setpoint positions at output of 4th transformation, i.e.
$AA_ITR[x,4] == $AA_IM[x]
If one or more transformations of the transformer chain are missing, the highest layers continue
to deliver the same values. If, e.g. Transformer 3 and Transformer 4 are missing, this
corresponds to:
$AA_ITR[x,2] = $AA_ITR[x,3] = $AA_ITR[x,4] = $AA_IM[x]
If the transformations are shut off via TRAFOOF or in RESET, the Layers 0 to 4 fuse together
and the variable always delivers the BCS value (Layer 0) in this case.
Axis
Either a geometry, channel or a machine axis name is permissible as the 1st index of the
variable. The assignment of the channel axes to the geometry axes corresponding to the 0
layer takes place during the programming of geometry axis name in each transformer layer.
Using geometry axis names is meaningful only if the geometry axes are not switched over.
Otherwise it is always better to use channel axis names.
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
M1: Kinematic transformation
7.4 Chained transformations
447