Siemens SINUMERIK 840DE sl Function Manual page 85

$AA_IBC: Actual setpoint of a cartesian axis
System variable $AA_IBC[ <axis>] determines the setpoint position of a cartesian axis lying
between BCS and MCS. If an axis is cartesian at the output of the nth transformation, then this
output value is delivered. If the corresponding axis at the output of all transformations is not
cartesian, then the BCS value including all BCS offsets of the axis are determined.
If TRACON responds to an axis as cartesian, then its MCS value is delivered. The used axis
name can be a geometry, channel or a machine axis name.
$VA_ITR: Actual value at the output of the nth transformation
System variable $VA_ITR[ <axis>, <transformation layer> ] determines the setpoint position of
an axis at the output of the n th chained transformation.
$VA_IBC: Actual cartesian BCS encoder position of an axis
System variable $VA_IBC[ <axis> ] determines the encoder position of a cartesian axis lying
between BCS and MCS. The used axis name can be a geometry, channel or a machine axis
name.
If an axis at the output of the nth transformation is cartesian, then this output value is delivered.
If the corresponding axis at the output of all transformations is not cartesian, then the BCS value
of the axis is determined.
$VA_IW: Current WCS actual value of an axis
System variable $VA_IW[ <axis> ] determines the encoder position of an inverse-transformed
axis in WCS. The WCS value contains all axis-related superimposition portions (DRF,
AA_OFF, ext. zero offset etc.) and offset values (CEC, etc.).
$VA_IB: Actual BCS encoder position of an axis
System variable $VA_IB[ <axis> ] determines the inverse-transformed encoder position of an
axis in BCS. The BCS value contains all axis-related superimposition portions (DRF, AA_OFF,
ext. zero offset etc.) and offset values (CEC, etc.).
Note
$VA_ITR$, VA_IBC, $VA_IW, $VA_IB
The value of the variable does not change while reading the variable within an IPO cycle,
although the actual value could have changed.
In active transformations, one must consider that the transformation of the actual values into
BCS in the IPO cycle can be very time-consuming. In this case one must set an adequate IPO
cycle.
Transformations
Function Manual, 06/2019, A5E47435470B AA
M1: Kinematics transformation
2.4 Chained transformations
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