Here's an example code snippet in C++ that demonstrates how to integrate a CoDeSys controller with ROS 2:
For a decade, engineers dreamed of merging these worlds: let the PLC handle the hard real-time I/O and safety, while ROS 2 handles the complex perception, path planning, and high-level decision-making.
There are several proven methods to bridge CODESYS and ROS 2. The choice depends on factors like performance needs, hardware constraints, and the nature of the project.
Then Mira, the automation engineer, had an idea that would change the plant’s heartbeat. She imagined CODESYS not as a siloed PLC runtime but as a bridge: controllers still enforcing safety interlocks and hard real-time motion, while ROS 2 orchestrated high-level behaviors, vision-guided corrections, and fleet coordination. She sketched a layered architecture on a napkin: CODESYS managing deterministic I/O and motion via its runtime, ROS 2 nodes running on edge computers for perception and planning, and a middleware translator whispering between them. The translator would expose ROS 2 topics as CODESYS variables and map CODESYS events into ROS 2 services—two ecosystems speaking through a well-defined protocol. codesys ros2
CODESYS and ROS 2 Integration: Bridging Industrial Automation and Advanced Robotics
ROS2, built on top of DDS (Data Distribution Service), is designed for high-throughput data flow. It creates a peer-to-peer network of nodes where a lidar sensor might publish a point cloud that is consumed by a navigation stack. It is highly flexible but introduces complexities regarding latency and determinism.
ROS 2 is an open-source software framework developed by the Open Source Robotics Foundation (OSRF). It is designed to simplify the development of complex robot applications by providing a flexible and scalable architecture. ROS 2 offers a wide range of features, including: Here's an example code snippet in C++ that
For extremely demanding applications, a more custom, low-level approach can yield incredible performance.
Historically, PLCs handled simple I/O and motion control, while a separate PC handled "smart" tasks like SLAM (Simultaneous Localization and Mapping). Integrating them directly offers several advantages:
While powerful, blending these two distinct architectural philosophies introduces specific challenges that engineering teams must address: Then Mira, the automation engineer, had an idea
| CODESYS type | ROS2 message type | Example | |--------------|------------------|---------| | BOOL | std_msgs/Bool | – | | INT, DINT, LINT | std_msgs/Int32, Int64 | – | | REAL, LREAL | std_msgs/Float32, Float64 | – | | ARRAY[0..5] OF REAL | std_msgs/Float32MultiArray | layout dim [6] | | STRUCT | Custom .msg | field-by-field |
We propose a layered architecture consisting of three logical planes: