Baumer BA UNxK09 IO - Manual (Page 4)

en_BA_UNXK 09-IO-Link.doc 4/18 Baumer Electric AG
24.04.2012/haa Frauenfeld, Switzerland
2 IO Link Introduction
In order to fully understand the various configuration options, these operating instructions describe the most
important aspects of the IO Link interface. More detailed information concerning IO Link, together with all
specifications, is available at
www.IO-Link.com .
IO Link is a standard interface for sensors and actuators. Devices (sensors, actuators) are connected to an
IO Link master via point-to-point connections. Communications between the master and the device are
bidirectional, via the device switching line. This interface permits measuring values to be recorded. An option
to configure the sensor via the IO Link is also provided. There are two modes of sensor operation: the
standard input/output mode (SIO mode) and the IO Link communication mode.
The master switches the sensor to the IO Link communication mode. In this mode, process data
(measurement data) are now continuously transferred from the sensor to the master, while requirement data
(parameters, commands) are either written to the device or read from it.
2.1 SIO Mode
After start up, the sensor is automatically in the SIO mode. In this mode, the sensor operates as a standard
switching or measuring sensor. On the master side, the IO Link port is set as a normal digital input. The
sensor can be used like a standard sensor without IO Link. However, various functions can only be controlled
with the aid of IO Link.
2.2 IO Link Communication Mode
The sensor is switched to the “communication mode” by means of a so-called “wake up” signal sent by the
master. With this action, the master attempts to locate a connected device by means of a defined signal
transmitted along the switching line. If the sensor responds, communication parameters are exchanged, after
which the cyclic transmission of process data can begin.
The following can be performed in the IO Link communication mode:

Process data can be received;

Parameters (SPDUs) can be read from the sensor;

Parameters (SPDUs) can be written to the sensor;

Commands can be transmitted to the sensor (e.g., switching point teaching, resets to factory
settings, etc.).
The process data contain cyclic data such as measuring value; switch status or quality information which is
transferred to the higher level controller.
The master can exit the IO Link communication mode by using a “fall back”, after which the sensor once
again operates in the SIO mode until it receives the next “wake up”.
The sensor’s behavior in the SIO mode can be adjusted in the IO Link communication mode. This allows the
sensor to be easily adapted to the requirements of corresponding parameters, and to then continue
operating as a “normal” sensor, without the use of IO Link. Alternately, the sensor can also operate
continuously in the IO Link communication mode in order to fully utilize the entire functional scope provided
by the process data.