IO-Link is an open standard, point-to-point communication link for sensors and actuators. It’s defined by the IEC 61131-9 international standard which specifies a single-drop digital communication interface technology (SDCI, commonly referred to as IO-Link) for sensors and actuators.
A typical IO-Link configuration includes an IO-Link master, which is the interface between the devices and a controller, such as a PLC. Devices can include sensors or actuators but can also be other devices such as hubs or robotic grippers or even power supplies with IO-Link connections. The master can be connected to virtually any fieldbus, and information flow between the master and devices is bi-directional. A key differentiator between IO-Link and standard IO is that with IO-Link, three types of data can be transmitted between the master and devices: process data, service data, and events.
It’s also important to note that IO-Link is not a fieldbus itself. Being fieldbus-independent, it can be integrated with and applied over various networks, fieldbuses, and backplane buses. IO-Link is a part of PROFIBUS & PROFINET International (PI), one of the world’s largest industrial automation organizations, where continued development includes IO-Link Safety and IO-Link Wireless.
(Image credit: Pepperl+Fuchs Control, Inc.)
IO-Link has a number of benefits that make it a viable alternative to other types of more traditional I/O setups, including reduced cost and complexity and improved efficiency.
A significant benefit of IO-Link is that it’s based on standard, unshielded, three-wire cables, so it eliminates custom cabling and connectors and simplifies wiring overall, particularly for analog devices. Plus, IO-Link relies on standards such as M12, M8 or M5 connectors, simplifying connections even further. And in case a device requires a power connection, a standard 5-wire cable can be used.
Comparisons are apt for several types of networking schemes, including analog and Ethernet-based methods. While many factories still use analog systems, these systems can suffer from data and accuracy losses during analog to digital conversion. But with IO-Link being entirely digital, it eliminates these losses.
With simple analog connections, there is an advantage for IO-Link in that it can offer much more. While both are not complex to integrate with standard connections, analog connections lack the digital advantages of real-time diagnostics that IO-Link offers.
With IO-Link, real-time data can be collected directly from devices on the factory floor, providing data about pressure, temperature, and other parameters as well as diagnostic data about individual devices.
In addition to the above-mentioned benefits, IO-Link supports IIoT and Industry 4.0 initiatives by providing more data about devices and machines, which lets users perform real-time monitoring and diagnostics and make better, faster decisions. In particular, the bidirectional communication feature allows for extended diagnostics of sensors and actuators, and simple and fast parameter setup.
With the added data from factory-floor devices that IO-Link enables, manufacturers can more easily monitor machine performance to predict potential failures. They can also proactively schedule machine maintenance and reduce unplanned downtime to extend equipment and machine life.
This is how IO-Link can help machine builders implement predictive maintenance and support larger Industry 4.0 initiatives.
Filed Under: Industrial automation, Motion Control Tips
