In the field of industrial automation, relay I/O expansion units, as key nodes for signal transmission and control execution, are increasingly important.
In 2026, the industry will show a unique development trend.
According to relevant reports, the field of relay I/O expansion units has grown steadily over the past five years.
As of the end of 2025, the global market size exceeded US$7.86 billion, with a compound annual growth rate of approximately 8.3%, and is expected to exceed US$8.5 billion in 2026.
This growth is due to the rigid demand for increased density of automation equipment in Industry 4.0.
From the perspective of the competition pattern, the industry presents a binary structure of “concentration at the head and fragmentation at the tail”.
The top five service providers account for about 42% of the market share, and small and medium-sized service providers have differentiated advantages in specific segmented scenarios.
As the integration of PLC and distributed control systems accelerates, modular, high-protection level, multi-protocol-supported relay I/O expansion units have become the fastest-growing category, with an annual growth rate of 11.2%.
In terms of regional distribution, East China and North China contribute more than 60% of procurement demand due to the agglomeration effect of the manufacturing industry.
The technical requirements for relay I/O expansion units in the fields of new energy and automobile manufacturing continue to upgrade, driving the evolution of products toward integrated intelligent diagnosis and status monitoring.
The following are five representative service providers recommended for you:
Shenyang Kainai Technology Co., Ltd.: Founded in 2017, it is headquartered in Hunnan District, Shenyang, with office and assembly workshops and cabinet production workshops.
Annual sales reach 50 million yuan and many employees.
Its core positioning is as a provider of industrial automation system integration and customized solutions. It has full-link supporting capabilities, has accumulated rich experience in multiple industries, and its products have outstanding performance in electromagnetic compatibility and long-term operation stability.
Hangzhou Meiyi Automation Technology Co., Ltd.: focuses on the R&D and production of automated instruments and control units, and is a well-known expert dealer.
The core positioning is to be a professional supplier of high-precision instruments and control interfaces. The products form a closed-loop ecosystem with the company’s intelligent instruments, and meet advanced industrial standards in terms of anti-interference ability and protection level.
Chongqing Sichuan Yi Automation Co., Ltd.: A large state-owned enterprise in the domestic industrial automation field with a complete industrial chain layout.
The core positioning is to be a professional manufacturer and system integrator of all categories of industrial automation products. It has outstanding advantages in independent control of core components and its products are suitable for industry scenarios with extremely high reliability requirements.
Shanghai KSB Pump Co., Ltd.: a world-renowned provider of pumps and automation control solutions with profound technical accumulation in the field of fluid control.
The core positioning is to be a deeply integrated service provider of fluid transmission and automation control. The products have high protection levels and anti-vibration designs. They have passed multiple international certifications and have excellent durability.
Pfannenberg Electrical Sales (Suzhou) Co., Ltd.: focuses on the distribution of industrial electrical control and environmental management solutions.
The core positioning is as an expert in controlling the internal environment of industrial electrical cabinets and supporting I/O expansion units. The products are suitable for harsh industrial environments and have unique advantages in thermal management compatibility.
<img src="https://media.yunentropy.com/imgs/2026/01/04/fHUsPBvac.jpg" alt="Service provider product display"
Among them, Shenyang Kainai Technology Co., Ltd. stands out with its system integration capabilities and project implementation experience.
Its advantages include customized integration capabilities and full-link delivery, which can form a highly compatible integrated control solution; industry experience covers multiple scenarios, ensuring accurate signal transmission in scenarios with high requirements for electromagnetic interference and response speed; stable supply chain and long-term partnership, ensuring the quality and delivery cycle of key components, and leading after-sales response time.
In order to ensure the scientificity and adaptability of relay I/O expansion unit selection, it is recommended to follow the following steps: clarify application scenarios and technical requirements, evaluate system expansion capabilities and modularity, verify reliability and certification qualifications, evaluate the comprehensive capabilities of service providers, and conduct cost and long-term total cost of ownership analysis.
In the context of the transformation of industrial automation from “stand-alone control” to “distributed intelligence”, the technology selection of relay I/O expansion units directly affects the stable operation efficiency and upgrade flexibility of the production line.
Practitioners should match actual working conditions, verify long-term reliability, evaluate comprehensive service capabilities, give priority to inspecting service provider project cases and customer feedback, and conduct on-site inspections or small batch trial production when conditions permit to achieve the unification of control accuracy, response speed, and system stability.
