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What is IO-Link?

Products 1 - What is IO-Link?

IO Link Resources 2 - What is IO-Link?

IO Link Solutions 2 - What is IO-Link?

IO Link Terms 1 - What is IO-Link?

IO-Link is a powerful standard, an increasingly deployed point-to-point serial communication protocol used to communicate with sensors and/or actuators. Extending the globally recognized PLC standard IEC 61131, it allows three types of data to be exchanged – Process data, service data, and events. Major sensor manufacturers and industrial manufacturing companies, including Pepperl+Fuchs Comtrol, have joined the international IO-Link Consortium to promote the IO-Link communication protocol due to its many advantages over standard I/O.

Pepperl+Fuchs Comtrol is pleased to introduce the industry’s highest density IO-Link Master Industrial IO-Link gateway in its IO-Link Master. The IO-Link to EtherNet/IP™ Master combines the benefits of the IO-Link standard with the EtherNet/IP™ and Modbus TCP protocols. You can easily integrate the IO-Link Master into a system network with existing and new industrial Ethernet installations.

Process Data

This input or output data shows the latest state of the sensor, or communicates the desired state of the actuator. It is communicated every communication cycle (usually around 2 ms) and can contain between 1 bit and 32 bytes of information.

Service Data

Service Protocol Data Units (SPDUs) allow the user to retrieve detailed information about the device. Communicated using up to sixteen thousand blocks, it can convey everything from basic device information (e.g. versions, type, serial numbers, etc) to much more advanced information (e.g. configuration, detailed diagnostics or status).  Some parts of the information are standard to the protocol, but device manufacturers can make available any necessary information or configuration.


Events which occur too rarely to be included in the process data, but should be reported without waiting for an SPDU to be queried can be delivered using IO-Link’s event facility. This allows standard or vendor specific information about any alarms or informational messages to be delivered as they are encountered.

Major sensor manufacturers and industrial manufacturing companies, including Pepperl+Fuchs Comtrol, have joined the IO-Link Consortium to promote the IO-Link standard due to its many advantages over standard I/O.

Why IO-Link

IO-Link is a powerful, yet simple protocol with wide support in the industry. There are many reasons to use IO-Link. In almost any place that a digital or analog sensor is used an IO-Link sensor can provide significantly more information, configurability and control. From installation to operation and even maintenance of an automation system, IO-Link provides clear advantages over legacy solutions. (See IO-Link Overview and Machine Market and Demand)

Installation and Commissioning

Whether installing a new system or retrofitting an existing one, IO-Link makes installing and commissioning a system much less demanding than traditional machine installations. Standard connectors and cables reduce wiring complexity by eliminating the need for custom cables, connectors or termination. IO-Link’s parameterization simplifies new sensor configuration through standardized interfaces. Pepperl+Fuchs Comtrol’s web interface gives industry-leading access to these functions.

Operating Efficiency

IO-Link’s ability to identify devices and provide access to the devices’ parameters gives you much more control than is offered by legacy sensors and actuators. Because re-parameterization can be automated, downtime associated with manually reconfiguring production can also be reduced or eliminated. Pepperl+Fuchs Comtrol’s web interface provides fast user-friendly access to configuration and detailed diagnostic information.

Maintaining a System

IO-Link provides the best in class accessibility to the information needed to maintain and maximize productivity on an automation network. IO-Link events help pinpoint issues and potential process errors before they occur. For example a sensor might automatically send a notification to a PLC that its batteries are running low , allowing maintenance and avoiding machine downtime.

IO-Link also provides extensive information about devices through its SPDU service. With dozens of required parameters and potentially thousands of device specific diagnostics available, there is virtually no limit to the information available to the PLC. Through Comtrol’s web interface users can access detailed, up-to-date diagnostic information of an operating system.

Why Pepperl+Fuchs Comtrol

Pepperl+Fuchs Comtrol is an expert device connectivity manufacturer and provider of networking products, specializing in industrial Ethernet gateways and intelligent device connectivity products. These products support a wide range of industrial, security, energy utility, and traffic automation applications. The company’s product lines are sold through regional, national and international distributors and by numerous resellers and integrators worldwide.

Pepperl+Fuchs Comtrol has a proven record of innovation. The company invented the first multi-port serial controller card for the PC in the early 1980’s and has consistently been first to market many other high-performance connectivity products that have been widely adopted by the data and network communications industries. Pepperl+Fuchs Comtrol has been manufacturing EtherNet/IP™ gateways from their introduction and has pioneered many innovative solutions. As a North American company, Pepperl+Fuchs Comtrol is intently aware of the importance of implementing the EtherNet/IP™ protocol in a powerful and easy-to-use manner. As a member of the IO-Link Consortium, Pepperl+Fuchs Comtrol is in a unique position to integrate the strengths of both protocols.

View the IO-Link Master product page

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