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IO-Link protocol for VFDs, sensors and actuators

Jonathan Bullick | October 15th, 2018
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At KEB America, we work with many different sized companies across a large range of industries, so we know how important it is to find a solution that works without a lot fuss or exorbitant costs. This is why we’ve chosen to design our products with flexible communication options, including the IO-Link protocol, available on our G6 Open Loop VFD.


The video above walks you through a simple IO-Link system using a Turck IO-Link block product acting as a hub between a KEB C6 Smart PLC, a G6 VFD and a motor, using COMBIVIS Studio 6 and IO-Link software for communication and programming.


The IO-Link communication protocol is used to transmit data between sensors and actuators and a linked industrial Ethernet device. The data is then used to analyze and optimize the operation and processes of the installation, preventing downtime and saving money.


Diagram of an IO-Link system used to link the HMI, PLC, and VFD to a sensor and tower light for safety
Diagram of an IO-Link system used to link the HMI, PLC, and VFD to a sensor and tower light.


What is IO-Link?

IO-Link is a digital, wired, point-to-point networking standard. It functions over a short distance – no more than twenty meters – using a standard four- or five-pin connector. The installation should have one IO-Link master to provide an interface to the controller or PLC.

The purpose of each IO-Link device connected to the master is to act as an intelligent sensor or actuator. The bulk of the data is used for preventative maintenance and servicing, such as the condition of an optical sensor that may need to be cleaned in the future. Diagnostic data sent via IO-Link devices is used to prevent future issues. Additionally, the information gathered by the device is read/write, allowing parameters to be adjusted by the PLC during operation in the case of on-the-fly adjustments.

There are four basic components of the communication protocol – ports, communication modes, data types, and transmission speeds. Communication ports physically located on the IO-Link master receive data – data about the state of the sensor or actuator, device details such as serial numbers or diagnostic information, or specific event notifications – and transmit it back to the PLC. The transmission speed can be configured to best suit the application and connected network.


Main benefits of the IO-Link protocol

System integrators can benefit from adding IO-Link devices to any installation that uses sensors. It is a non-proprietary and inexpensive solution to maintaining the health of a system’s sensors and actuators, and since it uses standard cabling and connectors, so retrofitting an existing system is easy. The passive connection structure also reduces the amount of wiring needed, and using IO-Link will eliminate the need for analog sensors. Another way IO-Link simplifies the system integrator’s job is by using stored data to make replacing components fast and easy. Simply swap out the old part, and the stored data can be written by IO-Link master on to the new part.

Key to running an automated system is minimal downtime and predicable maintenance. In previous blog posts we’ve covered how certain KEB products can help with the overall system maintenance. IO-Link has many of the same benefits including the availability of data that can be used for immediate adjustments or future commissioning. Process data can be sent from devices to the master, indicating things like measurements and statuses. The master can also send process data to networked devices to perform or adjust operations. Service or device data is read/write data about the sensor itself that the master will use to manage the system. Finally, there’s event data. Immediate notifications of errors or warnings of hazardous conditions can be the difference between a quick fix and days of down time. Event data sent from the sensors to the PLC via IO-Link will save time and money by alerting operators of small issues before they become large issues.


Industrial network market shares 2020 according to HMS Networks.


Since IO-Link is able to retrieve and report these pieces of data, we now have another major benefit – the ability to perform remote maintenance and commissioning of the sensors and actuators. The IO-Link software enables operators to assess the data and make adjustments as needed. It’s also possible to make quick adjustments to accommodate production changes without having to shut down the entire line.

Another benefit to using IO-Link is that the integrator can add sensors and actuators to any network, regardless of which protocol the system is already using. The master device will act as the bridge, using any of the popular communication options (pictured above) to communicate with the PLC.


Use cases for the IO-Link enabled G6 VFD

At KEB we work hard to be at the front of technology innovation. We’re proud to be one of the first to offer a variable frequency drive that can communicate with an IO-Link master, making machine commissioning and maintenance for motion control a possibility for automation systems of any size.


G6 VFD with IO-Link protocol
KEB’s G6 Drive with IO Link capability



The G6 Open Loop VFD has many of the features you expect from KEB’s family of drives including a range of available sizes and communication options. It can run our unique (A)SCL technology, eliminating the need for encoder feedback. An integrated braking transistor comes standard on the drive, and STO (Safe Torque Off) functional safety features are a popular option to add on to the drive. Now, with IO-Link enabled, the G6 drive can communicate with an IO-Link master to give all the benefits we discussed above.

Some motion control operations, like filling small pouches, will require both precise control and the use of sensors. With IO-Link the movements controlled by the drive and the measurements logged by the sensor can be wired, commissioned, and maintained on the same setup. This is also beneficial in setups where space is at a premium, or it spaces that are difficult to access. Less wiring and the ability to make adjustments from the PLC means less down time.

The G6 VFD from KEB America is available now for all of your IO-Link enabled networks, and our local sales and support team would love to discuss your application. Be sure to follow us on Facebook for more news and info, and our YouTube channel has a large library of informational videos about control and automation.

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