Hasan S. Cemkan
Corporate
- Thread Author
- #1
The Rise of Smart Sensors and the Port Shortage
The proliferation of smart sensors and actuators in modern manufacturing facilities is rapidly saturating the communication channels in existing control modules. To overcome this physical limitation, Murrelektronik has developed the IO-Link Multiplier, which quadruples a single master port. This reduces cabling and hardware costs while allowing more devices to be connected at the machine level.
Innovative Solution to Scalability Challenges
The increasing use of smart devices in modern production lines demands more data connection points. However, the number of ports on existing IO-Link master modules is often limited. When new sensors or actuators needed to be added, the traditional approach was to install additional master modules or expand fieldbus nodes. This created significant operational and economic disadvantages for electrical designers and system integrators. New modules took up space in the control cabinet, increased wiring complexity, and raised costs. Murrelektronik's IO-Link Multiplier offers a practical solution to these problems.
Operating Principle and Port Multiplication Architecture
Murrelektronik's IO-Link Multiplier is a compact component designed for decentralized automation. It connects to an existing IO-Link master port with plug-and-play logic, transforming this port into four independent and fully functional IO-Link ports. The module acts as a transparent concentrator and distributor for point-to-point serial data. The 32 bytes of IO-Link process data provided by the master port are flexibly distributed among the multiplier's four secondary ports, allowing bandwidth allocation to be adjusted to the specific requirements of each device.
This configuration preserves the full functionality of the communication standard. Cyclic process data, acyclic configuration parameters, and diagnostic information from the four connected devices remain fully accessible by the higher-level control system. Maintaining data transparency down to the field level facilitates automatic commissioning and speeds up troubleshooting during maintenance. Furthermore, LED status indicators on each port allow technicians to perform immediate visual diagnostics on the machine.
Technical Specifications and Cabling Flexibility 🔌
In addition to allowing simultaneous connection of up to four standard IO-Link devices via a single master port, the module offers flexible signal configuration options. Instead of IO-Link communication, the four ports can be used to receive up to eight standard digital inputs or drive up to four digital outputs.
The physical extension of the network topology is also an important technical feature. According to the IO-Link standard, the maximum length of an unshielded cable between a master and a device is limited to 20 meters. The IO-Link Multiplier acts as an active intermediate repeater station between the master and the end device, allowing up to 20 meters of cable length between the IO-Link master and the multiplier, and an additional 20 meters between the multiplier and the connected sensor or actuator. Doubling the total distance to up to 40 meters provides greater design freedom when routing cables in large machines or distributed systems.
The compact housing has an IP65/IP67 protection rating against dust, water jets, and temporary immersion. This feature makes the component suitable for direct mounting on equipment in harsh industrial environments, eliminating the need for junction boxes or secondary protective enclosures, and is compatible with cabinet-free automation concepts such as the company's modular Vario-X ecosystem.
Industrial Applications in Modular Systems and Retrofit Applications 🏭
In the manufacturing and plant engineering sectors, this device is primarily used in two operational scenarios: the construction of new modular machines and the technological upgrading of existing facilities.
In modular machine design, original equipment manufacturers can standardize the basic machine module with a reduced number of IO-Link masters and use the multiplier only in system variants that require optional sensor or actuator groups. This reduces bill of material costs for standard configurations and simplifies wiring variants.
In retrofit operations on active production lines, when adding sensors for condition monitoring or quality control requires new data acquisition points, the module allows for direct field expansion of the IO-Link infrastructure without altering the PLC architecture or purchasing new interface cards for the main fieldbus.
Technical Details and Protocol Performance 📊
To technically frame the function of the IO-Link Multiplier module within the IEC 61131-9 standard (which defines IO-Link technology), it is necessary to distinguish this architecture from traditional digital I/O hubs. While a standard IO-Link hub only collects binary signals (standard digital inputs and outputs) from multiple ports and routes them as bulk data to a single master port, an IO-Link multiplier or master-device hub maintains full-duplex serial communication (COM1, COM2, or COM3 modes) on each of its derived ports.
In terms of protocol performance, sharing a single master port with 32 bytes of process data among four secondary ports must be verified during the system design phase: the sum of input and output bytes generated by the four connected devices must not exceed the primary port's total 32-byte budget. Additionally, since the multiplier aggregates and routes data packets from the four channels to the master port over a single physical line, the overall cycle time of the master port will be higher compared to a single direct connection. Consequently, this technical solution is optimized for process sensors, measurement transducers, LED indicators, RFID readers, or pneumatic actuators with standard response time requirements (in the millisecond range); whereas for ultra-high-speed motion control applications, direct connection to dedicated master ports should be preferred.
In the industrial automation sector, component manufacturers address field channel expansion with different architectural approaches. Four or eight-port IO-Link master modules with integrated fieldbus interfaces (such as PROFINET, EtherNet/IP, or EtherCAT), produced by industry providers like Balluff, IFM Electronic, Turck, Pepperl+Fuchs, and Murrelektronik, offer 32 bytes of data and independent cycle times for each port, but require a dedicated network node, bus cables, and IP or field addressing.
