Q: What is an IODD?

IODD is the abbreviation for IO -Link D evice D escription. An individual IODD file exists for each IO-Link device. The device properties and individual sensor information such as identification, process and diagnostic data are stored here. These are required for integrating the sensor into the IO-Link infrastructure. ifm provides the IODD file for each IO-Link product on its website in the Download area and on the datasheet page for each product. In addition, the IODD of each IO-Link device sold by ifm is saved in the company's parameter setting software and in other software solutions for IO-Link device and port configuration tools from ifm. The IO-Link community also offers a manufacturer-independent IODD library in the IODD finder .

Question 1

What is IO-Link?

Accepted Answer

IO-Link is an open, standardized technology that allows the user to set up a point-to-point connection. IO-Link requires no sensor addressing. IO-Link components from companies that are members of the IO-Link consortium are compatible with each other.

Question 2

Is IO-Link a fieldbus?

Accepted Answer

No. In the automation structure, IO-Link is located below the fieldbus topology. IO-Link masters are used to connect the sensors to the fieldbus and the connected controller.

Question 3

How can I integrate IO-Link sensors into my controls system?

Accepted Answer

The process data transmitted by the IO-Link sensor can be read by the PLC without further conversion. Refer to Setup and support for more information.

Question 4

What is an IODD?

Accepted Answer

IODD is the abbreviation for IO-Link Device Description. An individual IODD file exists for each IO-Link device. The device properties and individual sensor information such as identification, process and diagnostic data are stored here. These are required for integrating the sensor into the IO-Link infrastructure.

ifm provides the IODD file for each IO-Link product on its website in the Download area and on the datasheet page for each product. In addition, the IODD of each IO-Link device sold by ifm is saved in the company's parameter setting software and in other software solutions for IO-Link device and port configuration tools from ifm.

The IO-Link community also offers a manufacturer-independent IODD library in the IODD finder.

Question 5

How do IO-Link sensors transmit measured values?

Accepted Answer

Via IO-Link, the measured values and process values are transmitted in a purely digital form - without conversions - from the sensor to the PLC.

Question 6

How does the IO-Link measured value differ from an analog signal (4…20 mA)?

Accepted Answer

The entire measured value transmission is digital. There are no conversions of the measured value. With analog signal transmission, the digitally measured value is converted into an analog signal in the sensor and transmitted to the PLC, where it is converted back into a digital signal. This transmission principle is prone to errors and conversion losses.

Question 7

Can wire break be detected with IO-Link?

Accepted Answer

Yes. The IO-Link master checks all IO-Link devices within a communication cycle. If a device does not respond, the wire break is immediately detected and signaled regardless of the measured value.

Question 8

Can IO-Link sensors alert to malfunctions?

Accepted Answer

Yes, this is done via events. A sensor (a device) can detect and signal an incorrect operating status to the master. This is done by setting a bit in the interface. The master reads this event and transmits it to the controller as a classic error code.

Question 9

What is an IO-Link master?

Accepted Answer

The IO-Link master establishes the connection between one or several IO-Link devices and the fieldbus system serving as a gateway. Refer to the product overview for more details.

Question 10

How do I configure the master?

Accepted Answer

Every master port must be configured by the user according to the requirements of the user's application: master port mode (DI, DO, IO-Link), process data width and data length. Refer to Setup and support for more information and setup videos.

Question 11

Can I benefit from IO-Link sensors without existing an IO-Link structure?

Accepted Answer

Generally, an IO-Link sensor also functions without an IO-Link infrastructure. In this case, it acts as a normal sensor and the additional information is not provided. However, if combined with the memory plug, E30398, IO-Link sensors can considerably simplify sensor parameter setting. It reads and saves the configuration data of a connected IO-Link sensor to make replacement simple and fast.

IO-Link frequently asked questions