Oct. 21, 2026
Industrial automation systems are becoming increasingly sophisticated. From programmable logic controllers (PLCs) and distributed control systems (DCS) to industrial computers and motion controllers, modern automation equipment relies on reliable electronic hardware to monitor processes, process data, and control machinery.
Behind these electronic systems is an important but often overlooked component: the subrack.
A well-designed subrack provides a structured mechanical platform for mounting printed circuit boards (PCBs), electronic modules, backplanes, connectors, and other components. It helps equipment manufacturers organize complex electronics, simplify maintenance, and develop modular control systems.
For industrial automation OEMs and system integrators, selecting the right subrack is an important step toward building reliable, serviceable, and scalable electronic equipment.
In this article, we explore the major applications of subracks in industrial automation, the design considerations that matter most, and how to select a suitable subrack solution for your project.
A subrack is a mechanical structure designed to accommodate electronic circuit boards, plug-in units, backplanes, and related components. Depending on the system architecture, it may be installed inside a larger equipment cabinet or integrated into a standalone electronic instrument.
Unlike a simple sheet-metal enclosure, a modular subrack can provide standardized mounting dimensions, PCB guide rails, front panels, connector alignment, and optional electromagnetic compatibility (EMC) shielding.
Many industrial electronic systems use 19-inch rack formats and standardized subrack dimensions defined by IEC 60297. Depending on the application, manufacturers may also use CompactPCI, VME, PXI, or proprietary modular architectures.
The subrack does not replace the PLC, controller, or electronic module. Instead, it provides the mechanical infrastructure that allows these electronic components to be installed, connected, protected, and maintained.
Typical subrack components include:
Aluminum or steel side panels and structural profiles
Horizontal rails and PCB guide rails
Front panels and plug-in unit handles
Backplanes and electrical connectors
EMC gaskets and grounding components
Cooling fans, fan trays, and thermal management accessories
The configuration depends on the board dimensions, connector arrangement, cooling requirements, and operating environment of the equipment.
Programmable logic controllers are widely used to control manufacturing equipment, assembly lines, packaging machinery, material handling systems, and industrial production processes.
Some PLC systems use compact modular housings, while high-performance or specialized control platforms may incorporate rack-based electronic assemblies.
In these applications, a subrack can support:
CPU and processing modules
Digital and analog I/O modules
Communication interfaces
Power supply modules
Signal conditioning and interface boards
A properly designed subrack helps maintain consistent module positioning and secure PCB mounting. Where plug-in modules are used, guide rails and front panels can also simplify module replacement during maintenance.
For automation equipment manufacturers, modular mechanical design can reduce the complexity of developing different hardware configurations.
Distributed control systems are commonly used in process industries such as chemical processing, power generation, water treatment, and industrial manufacturing.
DCS architectures may include controller modules, communication cards, signal processing units, power modules, and interface electronics distributed across multiple locations.
Subracks can provide a standardized mechanical platform for housing these electronic assemblies.
Important design considerations include:
Mechanical stability: Structural rigidity helps maintain board and connector alignment.
Electrical integration: The subrack must accommodate the required backplane, connectors, grounding arrangements, and cable routing.
Thermal management: Heat generated by processors, power modules, and densely packed circuit boards must be managed according to the system's thermal design.
Serviceability: Modular assemblies can help maintenance teams access or replace individual units without dismantling the entire system.
For DCS equipment manufacturers, these features support consistent hardware integration and easier long-term maintenance.
Industrial computers are used in machine vision, production monitoring, industrial networking, data processing, and human-machine interface applications.
Some systems use standalone industrial PCs, while others require modular plug-in electronics housed in standardized chassis.
Depending on the architecture, subracks can accommodate CPU boards, storage modules, communication interfaces, power supplies, and backplanes.
CompactPCI and VME-based systems are examples of modular computing architectures that can use compatible subrack structures.
For these applications, engineers should evaluate:
Board dimensions and insertion depth
Connector position and mating tolerances
Airflow and cooling capacity
Electromagnetic compatibility
Mechanical access for servicing
Compatibility with the selected computing architecture
A suitable subrack provides the mechanical foundation for the electronic system without unnecessarily restricting future hardware changes.
Motion control systems coordinate motors, servo drives, encoders, sensors, and real-time communication networks.
In industrial robotics, CNC equipment, and automated production lines, electronic control hardware must operate reliably despite electrical noise, repeated equipment operation, and sometimes significant mechanical vibration.
Subracks may be used in centralized motion controllers, multi-axis control platforms, servo system controllers, and specialized interface equipment.
Key design considerations include secure PCB retention, reliable connector alignment, grounding, and appropriate thermal management.
For equipment exposed to vibration or shock, the subrack structure and fastening method should be evaluated against the actual installation environment. Additional retention features may be necessary depending on the equipment design.
Industrial data acquisition systems collect information from sensors, instruments, production equipment, and test benches.
These systems may incorporate analog input cards, digital acquisition modules, signal conditioning boards, communication interfaces, and high-speed processing modules.
A modular subrack can help organize these components and provide a repeatable mechanical platform for different channel counts or hardware configurations.
For automated test equipment (ATE), subrack design may also need to consider frequent module insertion and removal, connector access, cable management, and heat dissipation.
Standardized mechanical dimensions can simplify the development of multiple system configurations, particularly when equipment manufacturers need to support different customers or product generations.
Industrial automation depends on reliable communication between controllers, sensors, drives, remote I/O systems, and supervisory software.
Industrial gateways, communication processors, network interface modules, and specialized data transmission equipment may use rack-mounted or modular electronic assemblies.
For these applications, the subrack may need to accommodate multiple circuit boards, communication connectors, power distribution components, and thermal management systems.
EMC design is particularly important where sensitive electronic circuits operate alongside switching power supplies, motor drives, and other potential sources of electromagnetic interference.
The effectiveness of the overall system depends on the complete enclosure and grounding design, not simply on the use of a metal subrack.
Industrial automation equipment is often expected to operate continuously and remain serviceable over a long product life cycle. The mechanical design of its electronic packaging therefore deserves the same attention as the selection of processors, connectors, and control components.
A modular subrack allows compatible electronic units to be arranged within a common mechanical structure.
When a system is designed for plug-in modules, individual units can often be inspected or replaced without removing the complete electronic assembly.
This approach can simplify maintenance, reduce unnecessary disassembly, and support future system upgrades.
Actual replacement procedures depend on the electrical architecture and whether the equipment supports safe hot swapping.
Electronic modules rely on stable mechanical support and accurate connector alignment.
A well-designed subrack provides mounting references for PCBs, front panels, guide rails, and backplanes. Dimensional accuracy is especially important when multiple plug-in modules must mate with a common connector system.
Material selection, structural rigidity, machining tolerances, and fastening methods should be determined by the equipment's mechanical requirements.
High-density electronic assemblies can generate substantial heat, particularly when they contain processors, power conversion modules, and multiple circuit boards.
Depending on the system, thermal management may involve natural convection, forced-air cooling, fan trays, heat sinks, or dedicated airflow channels.
Engineers should evaluate the expected heat load, ambient temperature, component temperature limits, airflow resistance, and installation orientation before selecting a subrack configuration.
A subrack provides the mechanical platform for the cooling solution, but its presence alone does not guarantee adequate heat dissipation.
Industrial equipment may operate near variable-frequency drives, switching power supplies, motors, and high-current conductors.
These environments can create electromagnetic interference that affects sensitive electronic circuits.
Where necessary, subrack designs can incorporate conductive structural interfaces, EMC gaskets, grounding points, and shielded plug-in units.
The required shielding performance depends on the system frequency range, enclosure configuration, bonding details, cable interfaces, and applicable EMC test requirements.
For demanding applications, EMC performance should be validated through appropriate testing of the complete assembly.
Industrial control equipment may remain in service for many years. During this time, electronic boards may change, components may become obsolete, or customers may request new interfaces.
A modular subrack can provide flexibility when a control system needs to accommodate revised board layouts or different module combinations.
Custom side panels, guide rails, front panels, mounting brackets, and backplanes can help adapt the mechanical structure to specific project requirements.
For OEMs, early coordination between the mechanical and electronic design teams can reduce integration problems during prototyping and production.
Selecting a subrack requires more than choosing a standard width and height. The mechanical structure must be compatible with the electronics, installation environment, and maintenance strategy.
Identify the PCB dimensions, number of modules, connector types, backplane arrangement, power requirements, and intended module insertion method.
If the system uses CompactPCI, VME, PXI, or another defined architecture, confirm compatibility with its mechanical and electrical interface requirements.
Determine the required rack format, height, width, depth, board insertion depth, and available cabinet space.
For standardized systems, verify the applicable edition and part of IEC 60297 or other relevant mechanical specifications.
Do not assume that every 19-inch enclosure is compatible with every plug-in module.
Consider ambient temperature, vibration, shock, humidity, dust exposure, and electromagnetic conditions.
For equipment installed in a control room, a factory floor, a mobile machine, or a transportation environment, the mechanical and environmental requirements may differ significantly.
Select the required protection and testing level based on the actual application rather than relying on a generic industrial label.
Estimate heat dissipation and determine whether natural or forced-air cooling is necessary.
Evaluate the grounding strategy, conductive contact surfaces, shielding interfaces, and cable entry points where EMC performance is important.
If formal compliance is required, identify the relevant test methods and acceptance criteria before finalizing the design.
For a customized automation platform, review whether the subrack supplier can support engineering drawings, mechanical modifications, prototypes, and repeat production.
Also clarify the required material, surface finish, tolerances, inspection procedures, and documentation.
Early supplier involvement can help resolve mechanical-electrical interface issues before they become expensive production changes.
RDEKONO provides modular electronic packaging and mechanical structure solutions for industrial equipment and other electronic applications.
Its product range includes IEC 60297 subracks, CompactPCI-related structures, shielded subracks, PCB guide rails, front panels, backplanes, connectors, and thermal management products.
Depending on the project requirements, these products can support the mechanical integration of electronic boards and plug-in assemblies in industrial control and instrumentation equipment.
Potential solution areas include:
Standard 19-inch subracks: For projects requiring standardized rack-mounted electronic packaging.
CompactPCI and VME-related structures: For compatible modular computing and control architectures.
EMC-shielded subracks: For projects that require attention to conductive interfaces and electromagnetic shielding.
Customized mechanical structures: For equipment requiring specific dimensions, board depths, mounting arrangements, or front panel configurations.
Integrated component solutions: For projects involving subrack structures, backplanes, connectors, and related accessories.
Explore RDEKONO's 19-inch subrack products and custom subrack solutions to learn more about available configurations.
The appropriate solution should be selected according to the electronic architecture, mechanical interface requirements, thermal design, and intended operating environment.
An industrial control cabinet is a larger enclosure that may contain power distribution equipment, PLCs, terminal blocks, drives, and other electrical components.
A subrack is a more specific mechanical structure used to house electronic boards, plug-in units, backplanes, and related components. A subrack may be installed inside a control cabinet or used as part of a standalone electronic assembly.
They can be suitable for PLC-based systems that use compatible rack-mounted or modular electronic assemblies. However, many standard PLC products use proprietary mounting systems or DIN-rail installations rather than 19-inch subracks.
The correct choice depends on the PLC platform, module architecture, and mechanical interface requirements.
IEC 60297 is relevant to the dimensions and mechanical arrangement of 19-inch rack and subrack systems. Depending on the application, other requirements may address environmental testing, EMC, shock, vibration, electrical safety, or railway-specific conditions.
The applicable standards should be identified according to the equipment's intended use and the customer's compliance requirements.
Yes. Depending on the manufacturer's capabilities, customization may include overall dimensions, board depth, guide rails, front panels, mounting brackets, shielding interfaces, and other mechanical features.
The customer should provide drawings, PCB dimensions, connector details, and environmental requirements to help establish a suitable configuration.
Useful information includes the required dimensions, PCB size and quantity, board insertion depth, connector or backplane details, material and surface finish, cooling requirements, EMC requirements, expected order quantity, and any applicable standards.
Engineering drawings or a reference assembly can help the supplier evaluate feasibility and provide a more accurate quotation.
Subracks are an important part of the mechanical infrastructure behind many industrial automation systems. From modular control platforms and industrial computers to data acquisition equipment and specialized communication systems, the right subrack helps organize electronic assemblies and supports mechanical integration, maintenance, and thermal design.
For equipment manufacturers, the best solution is one that matches the electronic architecture, installation environment, and long-term service requirements.
RDEKONO supports electronic equipment projects with standard subrack products and customized mechanical structure solutions.
Developing an industrial automation control system?
Contact RDEKONO to discuss your subrack requirements. Share your PCB dimensions, drawings, preferred rack format, and application environment so the engineering team can evaluate a suitable solution.
Website: https://www.rdekono.com/
Email: subrack@rdekono.com
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Oct. 01, 2023
For PCB board of the subrack insertion and extraction, Provides assistance when pulled out.Composed of four parts: handle, scutcheon, printed board bracket, and shaft. Handle material: PC+GF20%, Fire retardant standard: UL94V1, printed board bracket material: die-cast zinc alloy surface nickel plating.
Oct. 08, 2023
The subrack does not have a series of profiles, and after receiving an order, it is usually customized and processed according to the drawings. Products from different customers and products of different specifications from the same customer all need to be redesigned and processed, resulting in higher costs;