Technologies and components
Decentralized integration and modularity
Cabinet-free automation achieves decentralized integration by relocating automation components—such as controllers, I/O, drives, and power supplies—from centralized control cabinets to direct mounting on or near machines, distributing functions across the system for greater flexibility and reduced cabling.[1] This approach enables modular designs where individual components can be independently configured, expanded, or replaced to suit specific machine requirements without disrupting the overall architecture.[14]
Modularity relies on baseplates that serve as scalable backbones, incorporating electrical backplanes for power distribution, communication, and diagnostics through standardized connectors. Pluggable function modules, encompassing industrial PCs, I/O units, drives, and relays, attach directly to these baseplates via plug-and-play interfaces, eliminating extensive wiring and enabling rapid assembly or reconfiguration by non-specialized personnel.[1] The design supports hot-swapping of modules in many implementations and allows for flexible topologies, often leveraging real-time communication protocols like EtherCAT embedded in modules for seamless connectivity.[14]
Protection against harsh industrial environments is provided by IP67-rated enclosures, achieved through double sealing principles applied to housings and connectors to prevent dust and water ingress. Robust housing materials, such as metal with chrome plating or varnished finishes, ensure mechanical durability, electromagnetic compatibility, and resistance to oils, cleaning agents, and temperature variations, allowing reliable operation without additional protective enclosures.[1] Similar modular decentralized platforms employ compact, IP65/IP67-rated modules with quick-connection systems and integrated backplanes for secure, error-free installation in demanding conditions.[15][16]
Power supply and distribution
In cabinet-free automation, power supply and distribution are integrated directly into modular components, eliminating separate control cabinets and enabling decentralized, on-machine placement. This approach uses dedicated infeed modules to introduce power, specialized supply modules to generate required voltages, and baseplates or hybrid cabling for efficient forwarding and distribution across the system.[17]
In Beckhoff's MX-System, power infeed is handled by MS1xxx modules supplying protective extra-low voltages and low voltages, alongside MS2xxx EtherCAT power infeed modules that integrate stations into the EtherCAT network while providing power. Power supply modules (MS6xxx series) generate 24 V DC or 48 V DC in various power classes, with distribution occurring via the baseplate, where multiple potentials are made available to function modules. Power output modules (MS3xxx and MS4xxx) enable protected forwarding to substations, with cable protection and EtherCAT integration for extended distribution. Standardized connectors on the baseplate facilitate power forwarding, eliminating traditional wiring.[17][1]
Hybrid cables combine power signals, data communication, and EtherCAT in a single connector, simplifying connections and supporting power forwarding across modules. This design reduces cabling complexity while maintaining reliable distribution in IP67-rated environments. The MX-System complies with UL, CSA, and IEC certifications for global applicability without modifications.[1]
Bosch Rexroth's IndraDrive Mi employs a similar decentralized strategy, with hybrid cables daisy-chaining up to 30 drives in a string for combined power and communication distribution, eliminating distributor boxes and reducing wiring significantly. A supply module provides regulated DC bus voltage (typically 750 V), distributed via the common DC bus for energy sharing across drives. This enables flexible, scalable power forwarding directly within the machine.[7]
Control and communication
In cabinet-free automation, control and communication functions are integrated directly into modular, IP67-rated system components mounted on or near machines, eliminating traditional centralized control cabinets. Control is typically performed by embedded industrial PCs (IPCs) or compact controllers that deliver PC-based automation capabilities with high processing power and scalability, enabling direct execution of control logic close to the process. For instance, some systems incorporate dedicated IPC modules to handle the central control tasks.[1]
Real-time communication relies on industrial Ethernet fieldbus protocols, with EtherCAT being a prominent choice due to its deterministic performance and efficiency. EtherCAT operates on the master-slave principle, where a single Ethernet frame passes through all nodes and data is processed on the fly by hardware-based EtherCAT Slave Controllers, achieving cycle times in the sub-millisecond range and nanosecond-level synchronization via distributed clocks. This enables precise coordination of distributed components without additional switches or hubs, supporting flexible topologies such as line, tree, or ring configurations.[18]
Hot-swapping and hot-connect features are supported in many cabinet-free systems through the communication protocol, allowing modules or network segments to be added, removed, or replaced during operation without interrupting the overall system. This is facilitated by automatic node detection, dynamic reconfiguration, and minimal recovery times (often under 15 µs in redundant setups).[18]
Diagnostics are comprehensive and real-time, leveraging the fieldbus protocol for continuous monitoring and fault localization. EtherCAT-based implementations provide tools such as CRC checks, error counters, path quality assessment, and topology comparison during startup and runtime, enabling rapid identification of communication issues, cable faults, or hardware problems. These diagnostics are often accessible via centralized software interfaces or mobile apps with wireless connectivity (e.g., Bluetooth) for read-only access, supporting predictive maintenance and minimizing downtime in decentralized architectures.[19][18]
I/O and drive integration
In cabinet-free automation, the integration of input/output (I/O) and drive systems eliminates the need for centralized control cabinets by incorporating these functions into compact, modular, IP67-rated units mounted directly on or near machines. This decentralized approach combines multi-axis servo drives and versatile I/O interfaces within rugged housings, enabling plug-and-play connectivity, reduced wiring, and direct motion control at the point of use.[1][20]
Beckhoff's MX-System exemplifies this integration through dedicated pluggable modules. I/O modules (MOxxxx series) handle a wide range of digital, analog, and specialized signals required for sensors, actuators, and process monitoring, aligning with Beckhoff's extensive EtherCAT I/O portfolio for real-time communication and diagnostics. Drive modules (MDxxxx series) provide multi-axis servo and variable frequency drive capabilities, supporting diverse motor types and power levels in compact configurations. These modules mount onto standardized baseplates that supply EtherCAT networking, power distribution, and diagnostic data via a backplane, enabling hot-swappable installation without specialized wiring.[1]
Drive integration in the MX-System uses hybrid connectors (such as B17 or B23) that combine motor power, One Cable Technology (OCT) feedback, brake control, and motor temperature sensing via RTDs, streamlining connections and supporting precise motion control. Multi-axis setups consolidate multiple drives into single modules, reducing footprint and enhancing scalability for complex machine applications. The IP67-rated design protects against dust, water, and harsh environments, allowing reliable operation directly in the machine workspace.[21][1]
Bosch Rexroth's IndraDrive Mi complements this trend with intelligent, near-motor or motor-integrated servo drives that support cabinet-free configurations through modular, plug-and-play cabling, though its primary focus remains on drive electronics rather than combined I/O integration.[2]
This combined I/O and drive approach minimizes cable lengths, simplifies assembly, and enables faster diagnostics, making it well-suited for modular, Industry 4.0-aligned machine designs.[1][20]