This repository contains CANopenNode, a full-featured, portable ANSI C implementation of the CANopen protocol stack compliant with EN 50325-4 (CiA 301) and related standards (CiA 302, 303, 304, 305, 309). It is designed for embedded microcontrollers and real-time industrial automation systems. The stack implements Network Management (NMT) with heartbeat and node guarding, SDO server/client with expedited/segmented/block transfer, PDO with dynamic mapping, Emergency messages, SYNC, Time-stamp, LSS, Safety-Related Data Objects (SRDO), and an ASCII gateway for remote management (CiA 309-3). The architecture is modular, with each protocol in its own directory (301/, 303/, 304/, 305/, 309/). Central orchestration is provided by `CANopen.c` with a main processing loop `CO_process()` that should be called cyclically. The stack is configuration-driven via compile-time macros in `CO_config.h`, allowing feature enable/disable to reduce footprint. A hardware abstraction layer (`CO_driver.h`) separates CAN bus specifics, and example blank drivers (`CO_driver_blank.c`, `CO_storageBlank.c`) facilitate porting to new platforms. Key design patterns include a generic Object Dictionary interface with extension callbacks, a reusable circular FIFO buffer with protocol parsing, storage abstraction with CRC integrity, and non-blocking state machines. The codebase adheres to MISRA C:2012 (with documented exceptions) and includes Doxygen documentation. While primarily a library, the repository contains an example application skeleton and a generated device profile XML. Technical debt includes the FIFO and gateway modules being excluded from static analysis, certain static variables limiting reentrancy, and the trace feature being non-functional. The project is actively maintained with a large user base and multiple derivative repositories for specific platforms (Linux, STM32, PIC, etc.).
libplctag.NET is a .NET library providing two NuGet packages for industrial PLC communication via EtherNet/IP and Modbus TCP. The primary package (libplctag) offers a high-level, asynchronous, strongly-typed API built on top of the native libplctag C library, handling resource cleanup, exceptions, and event-driven operations. The second package (libplctag.NativeImport) exposes a low-level P/Invoke wrapper that manages platform-specific native binary loading and provides raw tag access. The architecture is a classic wrapper layer: the high-level Tag class encapsulates native handle lifecycle, attribute string generation, synchronous and async operations (using TaskCompletionSource with concurrent stacks to handle native callbacks), and exposes typed data accessors. The library targets a wide range of .NET frameworks (netcoreapp3.0 through net8.0, plus .NET Framework 4.7+), reflecting its industrial compatibility requirements. Some parts of the codebase (the generic Tag<M,T> and associated PlcMappers) are marked obsolete due to a planned API redesign (referenced as issue #406), indicating ongoing evolution.
This repository is a Java library for industrial communication protocols, providing implementations for Siemens S7 PLC, Modbus, Mitsubishi Melsec, RTSP/RTP/RTCP media streaming, and MP4 file format handling. The library features a modular architecture with clear separation by protocol, annotation-based serialization frameworks, and low-level utilities for binary data handling. It serves as an SDK for developers to integrate industrial device communication and media streaming capabilities into their applications. The code demonstrates consistent use of design patterns (builder, template method, annotation-based processing) and includes comprehensive test suites showing usage patterns.
Simple Open EtherCAT Master (SOEM) is a lightweight, portable C library that implements the EtherCAT master protocol stack. It provides full support for CoE (CANopen over EtherCAT), FoE (File over EtherCAT), SoE (Servo over EtherCAT), EoE (Ethernet over EtherCAT), Distributed Clocks (DC), SII (Slave Information Interface), and network redundancy (dual NIC). The architecture is modular: an OS abstraction layer (osal) encapsulates platform-specific threading, timing, and memory operations, while a hardware abstraction layer (oshw) handles raw network access via sockets (Linux, Windows, RTEMS, VxWorks, etc.). The core library functions (ecx_*) operate on a context structure, enabling multiple master instances. Key implementation patterns include an indexed buffer management system for out-of-order frame handling, a thread-safe mailbox pool and queue, and a circular error ring buffer. The library is not a standalone application; it is designed to be embedded into industrial real-time control systems. Sample applications demonstrate cyclic process data exchange, SDO access, EEPROM manipulation, and firmware updates. The codebase is mature (2005–2025) and under active development, with a dual GPLv3/commercial license. Some technical drift exists due to bundled third-party WinPcap headers and several platform-specific contributor directories that may lag behind core updates. Overall, the library demonstrates strong engineering with clear separation of concerns and portability, making it a solid foundation for EtherCAT master development.
FluentModbus is a .NET library that implements the Modbus protocol (TCP and RTU) for client and server communication. The library provides a full set of function codes (class 0, 1, and partial class 2) including read/write holding registers, coils, discrete inputs, input registers, and combined read-write operations. Both synchronous and asynchronous APIs are available. The server supports multiple unit identifiers, frame validation via a user-defined callback, events for register/coil changes, and configurable endianness. The client exposes high-level generic methods as well as low-level byte-oriented access. The codebase is well-structured with abstract base classes (MobusClient, ModbusServer), separate request handlers for TCP and RTU, and clean separation of concerns. Dependencies are minimal (logging abstractions, I/O, memory). The library includes comprehensive unit tests and samples.
FUXA is a full-stack web-based SCADA/HMI builder and runtime for industrial automation and IoT. It provides a visual editor (Angular + SVG) to create real-time dashboards, connect to field devices via 13+ protocols (Modbus, OPC UA, BACnet, Siemens S7, MQTT, etc.), and manage alarms, data acquisition (DAQ), scripting, scheduling, and user permissions. The backend (Node.js/Express) communicates with the frontend via Socket.IO for real-time device value updates. The system supports multiple time-series databases (SQLite, InfluxDB, QuestDB, TDengine) and can be deployed as a web server, Docker container, or Electron desktop app. It also integrates with Node-RED for low-code automation flows. The architecture is modular with a device driver factory pattern, JWT-based authentication, and a plugin system for extensibility. While the codebase is large and contains some monolithic components, it demonstrates solid engineering practices and has a rich set of reusable UI components and utility patterns.
modbus4j is a Java library implementing the Modbus protocol (ASCII, RTU, TCP, UDP) for industrial automation. It provides both master (client) and slave (server) functionality, supporting standard function codes (read/write coils, discrete inputs, holding/input registers, mask write) and a wide range of data types including BCD, floats, and custom swapped variants. The architecture is modular with separate transport layers, a generic messaging framework (MessageControl, WaitingRoom, Transport), and locator-based high-level access. The library includes a process image simulation for slave devices and batch read capabilities. It was originally developed for Mango Automation and has a parallel Java 1.4 backport (src_cdc) that indicates aging. The codebase shows good separation of concerns and reusable patterns but suffers from technical drift (RXTX dependency, manual byte manipulation, outdated build tools) and lack of modern testing infrastructure.