Allen-Bradley 1756 ControlLogix Instruction Manual page 158

Chapter 2 Motion Move Instructions
158
The operands are the same as those for the relay ladder MCCP instruction. For
the array operands, you do not have to include the array index. If you do not
include the index, the instruction starts with the first element in the array ([0]).
MOTION_INSTRUCTION Structure
Mnemonic
.EN (Enable) Bit 31
.DN (Done) Bit 29
.ER (Error) Bit 28
Description
The MCCP instruction computes a cam profile based on a given set of points in a
specified cam array. The resultant cam profiles generated by this instruction may
be used by subsequent Motion Axis Position Cam (MAPC) or Motion Axis Time
Cam (MATC) camming instructions to provide complex motion of a slave axis
with respect to either a master axis position or with respect to time.
Since cam profiles can be directly calculated by the Logix Designer Cam Profile
Editor, the main purpose of the MCCP instruction is to provide a method for
calculating cam profiles in real-time based on programmatic changes to the
corresponding cam arrays.
The MCCP instruction computes a cam profile based on a given set of points in a
specified cam array. The resultant cam profiles generated by this instruction may
be used by subsequent Motion Axis Position Cam (MAPC) or Motion Axis Time
Cam (MATC) camming instructions to provide complex motion of a slave axis
with respect to either a master axis position or with respect to time.
Specifying a Cam Array
In order to execute an MCCP instruction, a Cam array tag must be created using
the RSLogix Tag Editor or the Cam Profile Editor. The figure below illustrates
how the Cam array tags are established and used as input to the MCCP
instruction.
The Cam array elements consist of slave (yp) and master (xp) point pairs as well as
an interpolation type. Since there is no association with a specific axis position or
time, the x and y point values are unitless. The interpolation type may be specified
for each point as either linear or cubic.
Rockwell Automation Publication MOTION-RM002H-EN-P-February 2018
Description
The enable bit is set when the rung transitions from false-to-true and stays set until the done bit
is set and the rung goes false.
The done bit is set when the calculate cam instruction has been successfully executed and the
Cam Profile array calculated.
The error bit indicates when the instruction detects an error, such as if the cam array is of an
illegal length.