Io-Link Overview - Weidmuller UR20-4COM-IO-LINK Manual

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IO-Link overview

IO-Link for automation technology
IO-Link is a communication protocol for automation tech-
nology. IO-Link enables serial, bi-directional point-to-point
communication between devices on the sensor-actuator
level and devices on the field level or control level. Besides
cyclic process data, IO-Link allows parameters, diagnoses
and identification data to be exchanged acyclically. IO-Link is
standardised worldwide in IEC 61131-9 under the designa-
tion "single-drop communication interface for small sensors
and actuators" (SDCI).
An IO-Link system consists of two components:
– IO-Link master: represents the interface between IO-
Link devices and the superordinate communication sys-
tem.
– IO-Link device: communication-capable field device,
e.g. a sensor which is controlled by a IO-Link master.
IO-Link master and IO-Link device communicate via the
switching and communication cable C/Q. The IO-Link device
is supplied with voltage by the IO-Link master via the L+ and
L- cables. Depending on the port class, an IO-Link port has
additional connections:
– Port class A: The function of the additional connections
is selected by the manufacturer. Often, this connection is
occupied with an additional digital input or output.
– Port class B: The IO-Link master provides a second sup-
ply voltage via two further connections.
An IO-Link device is connected with an IO-Link port of the
IO-Link master with 3-cable or 5-cable technology.
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IO-Link communication principle
The IO-Link ports can be operated in IO-Link mode for bi-
directional communication or in SIO mode as digital inputs
or outputs. In IO-Link mode, the IO-Link master automati-
cally sets the right transmission rate for IO-Link commu-
nication after activation. The IO-Link master then checks
the identity of the IO-Link device (device comparison). The
Data Storage function ensures correct parameterization of
the IO-Link device after replacement of IO-Link device or
IO-Link master without additional programming.
You can parameterise IO-Link devices using a configura-
tion application or by means of acyclic services. To do
so, you will need the device description files from the
IO-Link device-manufacturer (IODDs). You can search for and
download IODDs using the "IODDfinder" on the IO-Link Con-
sortium website.
Manual Communication module UR20-4COM-IO-LINK
You will find more information on IO-Link and
IODDs at http://www.io-link.com.
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