The security of critical information infrastructure relies heavily on the stable support of industrial control systems.
In 2010, the Stuxnet virus attack on the centrifuges at Iran's nuclear facilities made the entire industrial community realize: once control devices such as PLCs and SCADA systems are compromised, attacks can be directly transmitted from cyberspace to production lines, power grids, and water conservancy hubs, causing real physical damage. Since then, the autonomous and controllable development of core industrial control software and hardware has gradually become a critical issue in global industrial development.
Industrial operating systems are widely used in national defense, security, economic, and livelihood sectors, and their security is directly related to the continuous safe production and operation of national infrastructure. Therefore, developing and producing autonomous, controllable, and intelligent domestic industrial control systems is a necessary approach to ensuring national industrial security and a strategic task that requires long-term commitment.
This is especially true for medium and large PLCs that undertake complex production process control tasks, where autonomous and controllable capabilities relate not only to core technological competence but also to the stable operation of critical industrial scenarios.
In recent years, as the national strategy of "autonomous and controllable, safe and reliable" has been deeply advanced, major infrastructure sectors such as electric power, petrochemicals, and water conservancy have increasingly demanded domestic substitution, particularly for PLCs—especially large PLCs—in critical fields where reliability and control performance requirements are extremely high.
01. A CNY 10.8 Billion Market with a Domestic Production Rate of Less Than 20%
According to MIR DATABANK data, the overall market size of China's PLC market will reach nearly CNY 17 billion in 2025, of which the medium and large PLC market size is approximately CNY 10.8 billion. In the medium and large PLC segment, foreign brands collectively hold a market share of over 80%, with Siemens alone accounting for nearly half, followed closely by Omron, Mitsubishi, and Rockwell, forming a competitive landscape of "one dominant player and multiple strong contenders."
Market Size of Medium and Large PLCs in China from 2021 to 2028
Data source: MIR DATABANK
In contrast, the market foundation for domestic medium and large PLCs remains relatively weak. In 2021, the market share of domestic brands was less than 10%; by 2025, this proportion has approached 20%, nearly doubling over five years with considerable growth. However, compared to foreign brands, there is still a significant gap in market share.
For a long time, foreign brands have established high market entry barriers relying on mature product systems, rich industry application cases, complete engineering toolchains, and long-accumulated user habits. The challenges faced by domestic manufacturers lie not only in product performance and reliability but also involve multiple aspects such as the technological ecosystem, engineering application experience, and user habits.
This market landscape not only restricts industrial upgrading to a certain extent but also hides potential risks at the supply chain security level. From this perspective, domestic substitution is no longer just an industrial development direction driven by policies, but an inevitable choice forced by the international landscape.
02. From Core Technology Autonomy to Ecosystem Synergy: What Hurdles Must Domestic PLCs Still Overcome?
True autonomy and controllability are not simply "domestic substitution," but require comprehensive consideration of core hardware, basic software, development tools, and related technological systems.
In fact, although China's industrial automation sector has achieved commercial application of domestic large PLC products, there is still external dependence in key technological links such as core components, underlying algorithms, and development platforms. Domestic large PLC manufacturers with full-stack autonomous and controllable capabilities for both hardware and software remain few. Representative manufacturers include Aotuo Keji, Baoxin Ruanjian, Helishi, and Zhongdian Zhike. The launch of their autonomous and controllable large PLC products undoubtedly represents a milestone breakthrough.
Large Autonomous and Controllable PLC Products from Some Domestic Manufacturers
For example, the large autonomous and controllable NJ series PLC from Aotuo Keji has achieved 100% domestication from chips and operating systems to programming software. The Tianxing series PLC from Baoxin Ruanjian has achieved full-stack autonomy and controllability in hardware design, real-time operating system, runtime system, compiler, and configuration programming software.
In recent years, leading domestic large PLC enterprises represented by Aotuo Keji, Baoxin Ruanjian, Helishi, and Zhongdian Zhike have successfully broken the long-term monopoly of foreign brands and achieved a historic leap in core lifeline industries related to national economy and people's livelihood, such as metallurgy, water conservancy and hydropower, rail transit, and petrochemicals, relying on profound technological accumulation and continuous innovation investment.
As the wave of the digital economy sweeps in, global manufacturing is accelerating its evolution from "industrial manufacturing" to "intelligent manufacturing." Especially as the digitalization, networking, and intelligence levels of industrial equipment continue to improve, PLCs also need to face new demands such as device interconnection, cross-terminal data interaction, application collaboration, and edge intelligence. How to expand the connection and collaboration capabilities between devices while ensuring real-time control, system security, and operational reliability has become a new topic for the further development of domestic industrial control products.
HarmonyOS, a full-scenario distributed operating system born for this era of Internet of Everything, provides a new technical path for the connection and application collaboration of industrial equipment relying on its unique design concept, advanced technical architecture, and strong ecosystem construction capabilities. It is becoming key to leading the industrial manufacturing field in providing an autonomous, controllable, and intelligently collaborative digital foundation.
03. Synergy Between HarmonyOS and PLCs: Promoting Industrial Control from Device Connection to Ecosystem Collaboration
At the 2026 Shanghai International Industry Expo, Aotuo Keji officially launched a new generation of autonomous and controllable PLCs based on the HarmonyOS operating system, equipped with domestic high-performance processors and integrated with industrial-grade NPU computing power. This includes three models: the NJ600 series large PLC, the NJ400 series medium and large PLC, and the NJ300 series medium PLC, covering full-scenario needs from medium to large scale, and from standalone to redundant systems.
The significance of this new product lies in the fact that it does not build the autonomous and controllable capabilities of domestic PLCs from scratch, but uses the original 100% domesticated NJ series as a foundation, further introducing the HarmonyOS operating system to explore the integration of domestic industrial control products with the HarmonyOS ecosystem. This series of products continues Aotuo's technological accumulation in the medium and large PLC field, and further explores the combination of domestic PLC control capabilities with the connection and collaboration capabilities of the HarmonyOS operating system, providing a new technical path for the autonomous, controllable, and intelligent development of industrial control equipment.
Among them, the standalone architecture of the NJ300 series focuses on lightweight and high cost-effectiveness advantages. With a streamlined architecture, flexible deployment, and convenient operation and maintenance, it is suitable for various small and medium-sized automation scenarios, helping enterprises reduce costs, increase efficiency, and efficiently complete intelligent upgrades.
The redundant architectures of the NJ400 and NJ600 series possess ultra-high fault tolerance and seamless fault switching characteristics, effectively avoiding production risks such as equipment downtime and system abnormalities. They are precisely adapted to core industrial control scenarios requiring high security, high reliability, and high precision, meeting the differentiated industrial control needs of various industries.
The NJ300 series CPU301-0161 exhibited on-site retains the original industrial control capabilities of the PLC while running OpenHarmony. It has currently passed the compatibility evaluation of the OpenHarmony 5.1.0 Release version and obtained the OpenHarmony ecosystem product compatibility certification and Dianhong certification.
At the same time, the PLC can serve as a HarmonyOS network node, establishing connections with mobile terminals and other nodes, providing a unified entry point for device management, mobile operation and maintenance, and cross-device collaboration.
During the on-site demonstration, it can be seen that when on-site sensors and I/O states enter the PLC, the relevant data can be transmitted to the HarmonyOS terminal through network connections and soft link mechanisms. The application identifies the PLC node and establishes a soft connection, providing a foundation for device status viewing, mobile operation and maintenance, and cross-device interaction.
For industrial sites, this means that a more direct interaction method is expected to be established between PLCs and mobile terminals. With the further development of related applications, more flexible implementation paths can be explored for device status viewing, on-site inspections, and some operation and maintenance operations.
Industrial Communication and Reliability: Meeting Control Needs Under Complex Working Conditions.
For critical industrial scenarios such as electric power, petrochemicals, and water conservancy, control systems still need to possess stable communication capabilities, reliable operational performance, and the ability to adapt to complex working conditions.
In terms of industrial communication, the PLC series products exhibited by Aotuo this time integrate Ethernet interfaces and natively support standard protocols such as MODBUS/TCP and OPC UA. They also cover mainstream industrial buses including ProfiNet, ProfiBus, DeviceNet, CANopen, EtherCAT, IEC61850, and serial ports, allowing seamless integration into various new and old production line communication architectures.
In terms of reliability, the hardware of this series adopts a multi-redundancy design, supporting power, CPU, I/O, and network redundancy, fundamentally eliminating single points of failure. The primary and backup systems achieve seamless, disturbance-free switching, with zero interruption in control output during the switching process. Coupled with fully intelligent I/O and hot-swappable design, it supports maintenance without shutdown, greatly improving operation and maintenance efficiency. For complex industrial environments, the product adopts a triple isolation design, supports wide-temperature operation from -40°C to 70°C, permanently saves data sources, and ensures no data loss after power failure, meeting the strict requirements of critical infrastructure for continuous operation.
On this basis, Aotuo Keji has also integrated AI capabilities into its products, with a built-in industrial-grade NPU supporting various precision operations including INT4, INT8, INT16, FP16, BF16, and TF32. The dual-core collaboration can flexibly adapt to multi-task and multi-scenario parallel processing needs. In terms of software ecosystem, the product is compatible with various deep learning frameworks such as TensorFlow, Caffe, TFLite, PyTorch, ONNX NN, and Android NN, providing computing power support for the deployment and application of industrial intelligent algorithms.
Overall, the products exhibited by Aotuo this time are not just adding an operating system to the PLC, but integrating domestic processors, industrial control capabilities, HarmonyOS connection mechanisms, and edge AI computing power into the same product system. This breaks the problems in the Industrial Internet of Things such as a wide variety of device types, high difficulty in terminal adaptation, difficulty in data interoperability between different devices and systems, and data silos, providing new exploration for the further development of domestic industrial control equipment in the direction of autonomy, controllability, and intelligence.
04. From Domestic PLCs to the HarmonyOS Ecosystem: How to Implement Autonomy and Controllability in Products?
Relying on a full-stack autonomous architecture and high-reliability hardware design, the Aotuo HarmonyOS PLC series can adapt to complex working conditions in multiple industries, covering different needs from small and medium-sized standalone applications to large redundant control systems. It can stably adapt to high-altitude and strong electromagnetic interference environments in scenarios such as water conservancy and hydropower, and rail transit.
From the perspective of product implementation, Aotuo's existing domestic PLC product system and modular engineering capabilities provide a foundation for further superimposing HarmonyOS connection capabilities. For example, the domestic automatic control transformation project of the Huangtian Sewage Pumping Station in Shenzhen adopts the NJ300 single-rack solution, configuring CPU, digital input and output, analog input and output, and communication modules to form a complete control system.
Typical Empowerment Scenario: Intelligent Control of Pumping Stations
In the intelligent control scenario of pumping stations, embedding an AI inference engine at the PLC edge can further expand the intelligent analysis and decision-making capabilities of the equipment.
For example, combining sensor data with AI models can enable real-time identification and early warning of water quality anomalies; by analyzing the operating status of equipment such as pumps and valves, potential faults can be identified in advance to achieve predictive maintenance; it can also dynamically optimize control strategies based on equipment operation, with comprehensive energy-saving effects reaching 10% to 30%.
By integrating AI inference capabilities into the PLC edge control link, AI capabilities that originally required the collaboration of PLC + industrial PC + cloud platform can now be completed on a single Aotuo HarmonyOS PLC.
From the hardware and software autonomy of domestic PLCs to the further integration of HarmonyOS connection capabilities and edge AI, the autonomy and controllability of industrial control are extending towards a more complete product system and application capabilities.
Summary
The difficulty of domestic substitution for medium and large PLCs lies not only in the autonomy of controller hardware but also in the long-term accumulation of basic software, development tools, engineering application experience, and the industrial ecosystem.
The HarmonyOS PLC exhibited by Aotuo this time provides a new observation sample for this process: while retaining the core control capabilities of the PLC, it explores the combination of domestic processors, OpenHarmony connection mechanisms, and edge AI, providing a new technical path for device interconnection and intelligent application expansion.
However, the exploration of technical routes does not mean that the difficulties of domestic substitution have been solved. Whether it can truly form a competitive advantage still depends on the continuous verification of product reliability, the degree of hardware and software autonomy, industrial scenario adaptation, security mechanisms, and long-term engineering practice. For medium and large PLCs, whether the HarmonyOS ecosystem can become a game-changing variable ultimately needs to be answered by specific applications and long-term operational performance.