Rockwell Automation 8520-9API 9/Series OCI API Developer's Guide - Manual (Page 63)

4–15 OCI Data Server Data Items
Publication 8520-6.6 - August 1999
All data items for axes are presented in the OCI API in “logical”
order with the exception of some AMP parameters which are defined
in physical axis terms. For example the data item
“DRILLING_AXIS_LOGICAL_BIT_PATTERN” is an example of a
axis data returned as a logical bit pattern.
Logical axis refers to the order that the axis are presented in the
process. For single process controls this is not much of an issue with
the exception of spindles and virtual axes which are always stored as
the last axes in the process.
Physical axis refers to the order in which the axes are created using
the ODS AMP tool and are independent of the process the axes are
assigned to.
Physical Axis
Number (order
AMPed)
Process
Assigned
Logical Axis
Process 1
Logical Axis
Process 2
Axis 1 X Process 1 1
Axis 2 Y Process 1 2
Axis 3 Z Process 1 3
Axis 4 U Shared 4 1
Axis 5 A Process 2 2
Axis 6 B Process 2 3
Axis 7 C Process 1 5
If looking at process 1 data item:
“DRILLING_AXIS_LOGICAL_BIT_PATTERN.1” axis data would
be returned in the bit pattern as X, Y, Z, U, C in the first five bits.
and for process 2:
“DRILLING_AXIS_LOGICAL_BIT_PATTERN.2” axis data would
be returned in the bit pattern as U, A, B in the first three bits.
Important: Only single process is available for Release 1 of 9/PC.
Logical vs Physical Axes