WIZnet Success Stories : GreenCS Environmental Integrated Controller
GreenCS’s Environmental Integrated Controller uses WIZnet’s new chip, the W55RP20, to achieve stable control.
1. Company Overview
GreenCS is a specialized developer of industrial environmental control systems, providing integrated solutions for precise monitoring and control across various industrial sites.
Their Environmental Integrated Controller is designed to manage multiple environmental parameters such as temperature, humidity, and air quality. In such systems, stable and reliable communication plays a critical role in ensuring real-time monitoring and control performance.
2. Project Background
GreenCS aimed to enhance the networking capabilities of their Environmental Integrated Controller by adding Ethernet-based communication.
While the existing system operated on Modbus RTU, integration with upper-level monitoring and centralized control systems required Modbus TCP support.
To achieve this, WIZnet’s W55RP20 was adopted as the Ethernet solution. Beyond simply enabling Modbus TCP, GreenCS required a customized implementation to meet specific operational demands.
3. Key Requirements
The primary requirements from GreenCS were:
- Maintain existing single-channel Modbus RTU
- Support Modbus TCP
- Operate as a Modbus TCP Server
- Allow two or more simultaneous Modbus TCP client connections
- Ensure communication integrity when RTU and TCP operate concurrently
However, GreenCS required a structure where multiple upper-level systems could simultaneously monitor and access the controller.
In summary:
- RTU: 1:1 communication structure
- TCP: 1:N structure (N ≥ 2)
- Concurrent request handling without compromising RTU stability
4. WIZnet Custom Implementation
WIZnet implemented a customized Modbus TCP solution based on the W55RP20, a high-performance SoC integrating an MCU and hardware TCP/IP stack, ideal for industrial Ethernet applications.
✔ Key Customization Points
- Designed a Modbus RTU ↔ Modbus TCP gateway architecture
- Implemented multi-socket management logic for Modbus TCP Server
- Enabled support for two or more simultaneous TCP client connections
- Developed a request scheduling mechanism to ensure sequential RTU processing
- Optimized session handling and buffer management to prevent data conflicts
A critical technical challenge was managing multiple TCP client requests while maintaining the integrity of the single RTU channel.
To solve this:
- Incoming TCP requests are queued internally
- RTU communication is processed sequentially
- Response mapping is carefully managed per session
- Communication latency is minimized
- Long-term operational stability is ensured
As a result, the system fully satisfies the multi-client requirement without compromising RTU communication reliability.
5. Results and Benefits
By integrating W55RP20 and implementing customized Modbus TCP functionality, GreenCS achieved:
- Simultaneous access from multiple upper-level systems
- Improved system scalability
- Enhanced flexibility in monitoring and control architectures
- Reliable Ethernet-based remote management
- Industrial-grade communication stability
The multi-client Modbus TCP capability significantly strengthens the product’s competitiveness in networked industrial environments and future smart factory integrations.
6. Conclusion
This project represents more than a simple Ethernet integration. It demonstrates a successful implementation of a custom multi-client Modbus TCP server while preserving RTU communication integrity.
Through WIZnet’s W55RP20 and tailored firmware development, GreenCS enhanced their Environmental Integrated Controller with a robust, scalable, and reliable Ethernet communication architecture.
WIZnet continues to support industrial customers with optimized Ethernet solutions and customized technical implementations tailored to real-world requirements.