Issue link: https://resources.mouser.com/i/1442859
26 | The Future of Robotics Texas Instruments Figure 1: Industrial communication by use case. However, for sensors and actuators, industrial Ethernet is often excessively robust and powerful. These systems usually require point-to-point communications rather than a fieldbus, and their bandwidth requirements are normally low. An innovative solution lies in IO-Link, a bidirectional communication protocol based on standard cabling and physical interconnection. IO-Link not only brings data from the factory floor to the PLC efficiently, but it also supports improved setup, diagnostics and maintenance, and is complementary to the existing fieldbus cabling. Since IO-Link and industrial Ethernet are complementary, it can benefit designers of networked factory systems to understand how the two standards work together. This white paper explains the differences between these technologies and discusses the range of solutions from Texas Instruments (TI) that can aid in Figure 2: Field Level Communication. industrial communication design. TI offers large portfolios of products supporting communications in general and overall industrial applications. A number of TI solutions are specific to communications in industrial automation, created with and backed by expertise gained from long-term relationships with customers. With strength in manufacturing technology and in-depth design support, TI can help industrial system developers strive to meet the needs of today's smart factories. IO-Link for low bandwidths Sensors and actuators are the most basic units of automation, feeding information into and acting on instructions from networked systems. Traditionally, these devices connect to control units through interfaces that provide little intelligence, and thus exchange little or no configuration and diagnostic information. Installing a new device requires configuration by hand at the point of use, and without diagnostics it is impossible to perform just-in-time preventive maintenance. IO-Link (International Electrotechnical Commission [IEC] 61131-9) is an open standards protocol that addresses the need for intelligent control of small devices such as sensors and actuators. This standard provides low-speed point-to- point serial communication between a device and a master that normally serves as a gateway to a fieldbus and PLC. The intelligent link established enables ease of communication for data exchange, configuration and diagnostics. An unshielded three-wire cable as long as 20 meters, normally equipped with M12 connectors, establishes an IO-Link connection. Data rates range up to 230kbps with a nonsynchronous minimum cycle time of 400µs, +10%. Four operating modes support bidirectional input/output (I/O), digital input, digital output and deactivation. Security mechanisms and deterministic data delivery are not specified. A profile known as the IO Device Description (IODD) contains communication properties; device parameters; identification, process and diagnostic data; and information specifically about the device and manufacturer. The many advantages of an IO-Link system include standardized wiring, increased data availability, remote monitoring and configuration, simple replacement of devices and advanced diagnostics. IO-Link permits factory managers to receive sensor updates and plan for upcoming maintenance or replacement. Swapping out a sensing or actuation unit that needs replacement and configuring a new one from the PLC through the IO-Link master eliminates manual setup and reduces downtime. Switching production remotely from one configuration to another without visiting the factory floor facilitates easier product customization. Factories can upgrade production lines readily to IO-Link, since it is backwards- compatible with existing standard I/O installations and cabling. Altogether, these capabilities result in reduced overall costs, more efficient processes and greater machine availability.