The application of IO-Link in Industry
In the era of Industry 4.0, intelligent automation relies on advanced control systems and continuous data exchange enabled by industrial connectivity, like IO-Link, to unify machine devices and facilitate advanced monitoring and diagnostics.
Standardized networks and communication-equipped devices are the foundation of industrial connectivity. While numerous protocols exist, not all meet the demands of modern automation for data exchange and intelligence. IO-Link was developed to address these requirements across a range of applications.
IO-Link is a wired point-to-point communication protocol that enables bidirectional data exchange between devices. Local controllers typically have multiple IO-Link ports for various devices, making it a point-to-point protocol.
Introduced in 2009 by a consortium?of 41 members, IO-Link has gained widespread acceptance for optimizing operations, reducing downtime, and cutting costs.
Defined by the IEC 61131-9 standard, IO-Link is supported by various manufacturers such as Siemens, Omron Automation, IFM, Balluff, Cinch Connectivity Solutions, Banner Engineering, Rockwell Automation, Sick, Pepperl+Fuchs, and others.
IO-Link is widely used in assembly automation, machine tools, and intralogistics for status communication, machine control, and enhancing device intelligence.
IO-Link mode enables two-way communication with field devices for data collection during monitoring, testing, and diagnostics. Primary ports in DI mode accept sensor inputs, while DQ mode ports function as digital outputs, typically for actuators or PLC instructions. These primary ports can switch modes, like transitioning from DI to IO-Link for diagnostics and monitoring data from sensors.
IO-Link application 1 of 3: actionable status communications
IO-Link devices enable machine monitoring and support system adjustments. In the machine-tool industry, IO-Link pressure sensors verify workpiece clamping, reducing rejected workpieces. These devices also aid maintenance by reporting status, like position sensors on assembly machines ensuring alignment. Analysis?of IO-Link diagnostics data allows technicians to predict and prevent errors and identify areas for operational improvement.
IO-Link application 2 of 3: advanced control and automation
IO-Link supports control and automation functions, often connecting to a higher-level PLC or host system for autonomous?operations. This connection typically utilizes standardized fieldbus or Ethernet protocols. Many IO-Link primaries come with fieldbus or Ethernet ports. In advanced control applications, devices integrate in one of three ways:
1/Direct connection to the host computer or PLC.
2/Connection to an IO-Link primary using the IO-Link protocol.
3/Use of IO-Link compatible?communications, connecting to an IO-Link primary via an IO-Link hub.
IO-Link hubs link non-IO-Link devices to the primary. With fieldbus and Ethernet connectivity, long-distance placement of IO-Link primaries is possible, whether in a control cabinet or at the outermost machine points. In advanced assembly, IO-Link primaries act as low-level controllers, handling both digital and analog signals, such as data from XY stage linear encoders. They serve as gateways, transmitting processed field-device data to PLCs or other system controllers.
IO-Link application 3 of 3: device intelligence
IO-Link's third application is enhancing devices' intelligence. IO-Link-enabled sensors can receive instructions, perform self-testing, and provide detailed data, beyond simple on-off signals. For instance, IO-Link temperature sensors continuously report precise temperature values for better process automation.
IO-Link's compact physical connections contrast with bulkier fieldbus and Ethernet interfaces, making it suitable for smaller field microdevices. IO-Link also enables precise control, allowing actuators to respond to specific conditions rather than basic on-off commands.
Input devices like pushbutton switches from suppliers such as Rafi can leverage IO-Link for smart features, including color-coded indicator lights.
However, IO-Link has limitations, being a wired protocol with a 20m cable length constraint and a 32-byte data transmission limit per cycle, making it unsuitable for data-intensive devices like cameras.
Summary:
IO-Link systems offer versatile applications, seamlessly integrating with existing protocols for extensive control and data collection systems. Their appeal lies in simplicity, with just an IO-Link primary, devices, and connectorized cables. Easy plug-and-play installation and cost-effectiveness further enhance IO-Link's advantages.
The IO-Link consortium's collaborative efforts have ensured broad compatibility among controllers, devices, and actuators from various manufacturers, providing design engineers with a wide array of equipment choices for specific use cases.