Simulation and Code Generation of Motion Instructions
The Simulink® PLC Coder™ software supports a workflow for the behavioral simulation and structured text code generation for the Rockwell Automation® RSLogix™ motion control instructions.
Workflow for Using Motion Instructions in Model
This workflow uses the Simulating and Generating Structured Text Code for Rockwell Motion Instructions example in the
plccoderdemos folder. This example provides a template that you can use
with motion instructions. It contains the following files:
Simulink model containing an example Stateflow® chart for modeling motion instructions.
Simulink library with a Stateflow chart that is used for modeling a real world drive (axis) with trajectories, delays, and other parameters.
MAT-file containing the bus data types for the
MATLAB® class file for implementing trapezoidal velocity profile. This is
used to simulate the behavior of the
Supporting file for code generation.
MATLAB enumeration class file that represents the type of motion API calls.
Helper file to avoid name mangling and reserved keyword limitations.
Function that transforms the chart in the model to make it suitable for code generation.
Before you start, copy the files in the example to the current working folder.
Create a Simulink model with a Stateflow chart.
Load the bus data types from the
MotionTypesForSim.matfile into the workspace by using the
Create data that represents the drive and motion instructions for the chart. For information on adding data to Stateflow charts, see Add Stateflow Data (Stateflow)
Copy the drive(axis) model from the
DriveLibrary.slxfile into the Stateflow chart. The drive model must be copied as an atomic subchart.
The drive logic Stateflow chart models a real world drive with parameters such as trajectory and delay. Any drive subchart has the following data:
Use the Subchart Mappings dialog to map the drive subchart data store memory data with the local data of the appropriate names in the container chart. For more information, see Map Variables for Atomic Subcharts and Boxes (Stateflow). The Simulating and Generating Structured Text Code for Rockwell Motion Instructions example has the following mapping for
Use graphical functions to create motion API instructions. For example, for the
Motion Servo On (MSO)instruction:
The mapping between the inputs to the outputs is through "pass by reference".
Create the controller logic in another subchart and use the motion instructions created in the previous step in the chart.
Controller1in the example has the following Stateflow chart.
Simulation of the Motion API Model
You can run simulation on the model containing the motion instructions and see the state
changes the controller chart and the
Drive subchart. You can also log the
local data of the chart such as
AXIS and the
MOTION_INSTRUCTION variables For more information, see Configure States and Data for Logging (Stateflow).
At the end of simulation, the logged signals are captured in the base workspace as a
logsout. This can be imported into Simulation Data
Structured Text Code Generation
plcgeneratemotionapicode function to prepare the model for
code generation and generate structured text code. The
plcgeneratemotionapicode takes the full path name of subsystem
containing the original chart as an input and creates a new model from which structured text
code can be generated.
Adding Support for Other Motion Instructions
plcdemo_motion_api_rockwell example has support for only the
following motion instructions:
To use other Rockwell Automation
RSLogix motion instructions in the model (For example,
Motion Axis Jog
(MAJ)), you must perform the following steps:
MAJinstruction is similar to
MAMinstruction, create a bus for
MAJwith elements similar to that of
MotionTypesForSim.matfile with the new definitions for
In the Stateflow chart, create a graphical function representing
MAM). Assign the appropriate inputs and outputs.
Create single transition with commands to set the output values.
Remove the transition commands and copy the graphical function to the
functionNamevariable in the
getDriveTemplateNames.mfile to include
DriveLibrary.slxfile to respond to
MAJcalls during simulation.
isMAJgraphical function (similar to
Drivesubchart to respond to
MAJby implementing required transitions etc (similar to
Create or update the controller logic as required. Create a new state and add
MAJinstruction to it (similar to the
Perform simulation and generate code using the steps described earlier.