---
title: "WIZnet Success Stories : GreenCS Environmental Integrated Controller"
url: "https://maker.wiznet.io/Alan/resellers/wiznet-success-stories--greencs-environmental-integrated-controller/"
markdown_url: "https://maker.wiznet.io/Alan/resellers/wiznet-success-stories--greencs-environmental-integrated-controller/md"
type: "VAR: Value-Added Reseller Products"
author: "GreenCS"
author_url: "http://www.gcsmagma.com/main.php"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "GreenCS"
original_url: "http://www.gcsmagma.com/main.php"
published: "2026-03-02"
language: "en"
likes: 0
views: 598
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# WIZnet Success Stories : GreenCS Environmental Integrated Controller

> GreenCS’s Environmental Integrated Controller uses WIZnet’s new chip, the W55RP20, to achieve stable control.

Original author: GreenCS (source: http://www.gcsmagma.com/main.php)

## Article

### 1. Company Overview

![](https://maker.wiznet.io/upload/ckeditor5/592358749%5F1772473786%2Epng)

[**GreenCS**](http://www.gcsmagma.com/eng/main.php) 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

![](https://maker.wiznet.io/upload/ckeditor5/592358749%5F1772473778%2Epng)

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**](https://docs.wiznet.io/Product/Chip/MCU/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

![](https://maker.wiznet.io/upload/ckeditor5/592358749%5F1772473754%2Epng)

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

![](https://maker.wiznet.io/upload/ckeditor5/592358749%5F1772473822%2Epng)In many embedded systems, Modbus TCP servers are typically implemented to support only a single client connection due to resource limitations.

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

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### 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

1. Designed a **Modbus RTU ↔ Modbus TCP gateway architecture**

2. Implemented **multi-socket management logic** for Modbus TCP Server

3. Enabled support for **two or more simultaneous TCP client connections**

4. Developed a **request scheduling mechanism** to ensure sequential RTU processing

5. 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.

![](https://maker.wiznet.io/upload/ckeditor5/592358749%5F1772474045%2Epng)

*[**WIZnet Custom Service request**](https://direct.wiznet.io/custom-service-request)*

---

### 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.

---

Source: https://maker.wiznet.io/Alan/resellers/wiznet-success-stories--greencs-environmental-integrated-controller/