OpenCN: Hard Real-Time Motion Control for Embedded and Industrial Automation
In industrial automation, robotics, and CNC systems, achieving hard real-time determinism is crucial for safety, precision, and performance. Many systems rely on costly proprietary solutions to meet those demands—but OpenCN offers an open, modular alternative specifically built for embedded motion control with microsecond-level timing precision. Released under the GPLv2 license, OpenCN promotes transparency, adaptability, and long-term sustainability—making it an excellent foundation for building reliable, real-time automation systems without vendor lock-in.
OpenCN is ideal for developers and integrators looking for affordable, real-time, and production-grade control systems that don't compromise on timing guarantees or long-term maintainability.
OpenCN originates from the well-known LinuxCNC project, whose architecture has powered machine tools and motion platforms for decades. However, traditional LinuxCNC relies on either soft real-time or hybrid userspace/hard real-time setups, often with considerable complexity or overhead.
🧠 Real-Time Core: Xenomai/Cobalt, Streamlined and Evolved
At the foundation of OpenCN lies a customized hard real-time core based on Xenomai/Cobalt. Unlike traditional implementations, OpenCN’s version removes the I-Pipe layer—a legacy abstraction once required to enable real-time co-kernels within Linux. This results in a lighter, cleaner, and more maintainable integration with the Linux kernel.
This architecture not only reduces latency and jitter but aligns with the forward-looking design principles of Xenomai 4 / EVL—while retaining the mature and proven scheduling and interrupt management features of Cobalt.
Benefits include:
Hard real-time determinism
Reduced system overhead
Compatibility with recent Linux kernels
Customizability for embedded deployments
The overall picture below shows the general OpenCN environment.
⚙️ Multicore Isolation for Determinism
OpenCN fully leverages asymmetric multicore processing, a key strategy for ensuring hard real-time behavior in modern multi-core systems. This allows:
Time-critical control loops to run on dedicated CPU cores
Background tasks such as networking, data logging, or user interfaces to be confined to separate cores
A predictable and interference-free real-time environment
This isolation model is essential for systems where control loops must execute with fixed cycle times, regardless of system load.
💻 Runs on x86 and Raspberry Pi 4/5
OpenCN runs natively on both:
x86 industrial PCs for performance-intensive applications
ARM-based platforms, including Raspberry Pi 4 and 5, for compact and low-cost deployments
This range of support makes it well-suited for:
Prototyping motion systems
Retrofitting legacy equipment
Deploying cost-sensitive automation solutions
Educational and academic use cases
Despite its efficiency, OpenCN delivers the hard real-time behavior expected in high-end industrial controllers.
🔌 EtherCAT for Real-Time Industrial Communication
OpenCN includes native support for EtherCAT drivers, allowing deterministic, synchronized communication with:
Servo and stepper motor drives
I/O expansion modules
Distributed sensors and actuators
EtherCAT is the primary fieldbus supported, ensuring seamless integration into modern industrial automation ecosystems. This makes OpenCN particularly well-suited for motion control platforms, where high-speed field communication is critical.
📡 User Interface and System Monitoring
OpenCN includes a remote user interface, which can run on a separate PC or tablet. This interface allows users to:
Configure the system
Monitor machine operations in real time
Visualize and log control signals
Optimize control parameters based on process feedback
Such capabilities are essential for maintaining high precision and quality in automated machining and robotic workflows.
🛠 EDGEMTech: Your Partner for Real-Time Embedded Control
At EDGEMTech, we have deep experience with OpenCN—many of our engineers were directly involved in its development and deployment. We offer:
Long-term support and maintenance
Custom adaptations to specific hardware platforms or motor drive integrations
Kernel and driver-level customization to meet hard real-time requirements
Consulting on deploying OpenCN in production systems or as part of Industry 4.0 strategies
Whether you’re building a CNC machine, an advanced robot, or a precision automation line, EDGEMTech can provide the expertise and support to make OpenCN a stable, tailored, and sustainable solution.
🔧 Summary
OpenCN proves that hard real-time control, open-source freedom, and embedded efficiency can go hand in hand.With native EtherCAT support, deterministic execution, and lightweight architecture, it offers a powerful foundation for next-generation control systems.
We invite you to share your experiences, ask technical questions, or explore OpenCN's capabilities with us here in the Realtime Systems section.
Let’s build deterministic systems—together.