FAQs

How is IO-Link positioned?

IO-Link is typically used in an automation environment below the I/O level for individual linking of field devices.

Where is IO-Link used?

IO -Link is used predominantly in an industrial environment in automated production for linking sensors and actuators.

What setting options do I have with IO-Link capable sensors and actuators?

This depends on the possibilities implemented by the manufacturer, but in general:

  • Local operation using teach-in, setting potentiometers, etc.
  • Event-driven program running using a connected controller
  • Operator-driven program running, e.g. using an HMI interface
  • Engineering system
  • Installation of a sensor in a pre-planned automation station with stored basic sensor settings

This also enables dynamic changing of parameter settings. Automated new settings are also possible.

Is it possible to upgrade existing systems in existing field bus structures?

As long as the system map of IO-Link has already been implemented for the bus system in question, an expansion of existing bus systems is possible.

Is it possible to manually adjust the sensor or actuator?

This is a matter of the implementation stage on the part of the component manufacturer. In principle, local parameter setting can be completely blocked or enabled.

How does IO-Link function?

IO-Link is based on the familiar 3-conductor connection for a digital switching signal, in which the switching signal is issued as a serial telegram. This means additional information can be exchanged in the form of a serial protocol between the I/O level and the field device.

Is IO-Link another field bus?

No, IO-Link describes a point-to-point connection between a peripheral interface and a field device.

How long can the connection between interface and field device be?

The maximum extension for each individual connection is 20 m.

How fast is the transmission of a signal over an IO-Link connection?

The typical signal transmission time for a value of 16-bit length is 2 ms.

Is it possible to send safety-relevant data, such as E-Stop commands, over IO-Link?

Transmission of safety-relevant data is not planned at this time.

Is it possible to use an intrinsically safe signal?

No, IO-Link is system-constrained to preclude an intrinsically safe signal.

How is power enabled on actuators?

The potential-free contact is implemented on Pins 2 and 5. Here you would use a 5-conductor standard cable.

What do I need to watch for when wiring?

Standardized 3-conductor cables or, in the control cabinet, individual leads are used. No shield is required.

What kinds of connectors are required on the sensor side?

All kinds of connectors used today. No special IO-Link cables or connectors are required. The recommended minimum gauge values must be observed. For 20m cable length the min. cross-section is 0.34mm≤. Since unshielded cables can be used, M8 and M12 standard connectors are suitable.

What data are sent over IO-Link?

Process data (e.g. analog values, switching states) are sent cyclically, configuration data (e.g. activation, deactivation of functions) as well as identification data (manufacturer ID) typically at startup, and parameters (sensitivity, switching threshold) or diagnostics are sent as needed.

What happens when an IO-Link proximity switch is defective and no equal replacement is available?

An IO-Link proximity switch (one switching output) can also be replaced by a corresponding standard proximity switch. Not available then are automatic identification, re-parameterizing and other communication functions. In this case only the switching signal is sent.

What non-IO-Link capable sensors can be connected to an IO-Link Master?

Standard PNP outputs or push-pull outputs.

Is mixed operation of IO-Link and conventional devices possible?

Both device types can be operated in a system, since each IO-Link component has by specification the conventional switching operation as well.

What is IO-Link with respect to AS-i?

  • A supplement system for intelligent wiring systems like AS-Interface
  • IO-Link is based on conventional point-to-point wiring
  • IO-Link is directly integrated in the sensor
  • IO-Link requires no special cables
  • IO-Link requires no sensor addressing
  • IO-Link has no station limitation

Is IO-Link a competitor of AS-i?

No, because

  • It is point-to-point wiring
  • It is a supplementary system on the lowest field level
  • If offers no bus-typical line or star topology

Why is IO-Link needed?

IO-Link is needed because:

  • It closes the communication gap in the lowest field level
  • It makes validation of machines and equipment possible down to the lowest sensor and actuator level
  • It minimizes the variety of existing interfaces (PNP, push-pull, 4-20mA, 0-10V, RS232, and RS422 become IO-Link)

What changes at installation and during use?

  • Nothing changes in terms of wiring - IO-Link uses the well known standard sensor cables M12, M8, M5
  • IO-Link replaces cumbersum transmission of analog signals over shielded cable
  • IO-Link replaces costly multipole parallel wiring by a simple 3 wire standard cable
  • IO-Link standardizes interfaces and cables with a single type
  • IO-Link provides transparency down to the field device level

Which type of sensors can be connected in the SIO-mode of IO.Link

  • Binary Sensors with PNP output can be connected
  • Sensors with NPN output cannot be connected

Is the system simpler than familiar communications structures?

  • Higher order communications structures are generally bus systems
  • IO-Link is a point-to-point connection

How do I incorporate the system into familiar bus systems?

A part of project planning of sensors and actuators, expansions are added to the engineering tools. The device-specific data are provided, depending on the engineering tool, using specific device descriptions and parameter setting interfaces (based on IODD description files or DTMs or proprietary tools.