The IO-Link master first attempts a communication with the highest defined data
transmission rate. If this transmission attempt fails the IO-Link master attempts a
communication with the lowest data transmission rate. The device always supports only one
defined data transmission rate.
If the master receives a reply, communication starts. First they exchange communication
parameters. If necessary the parameters stored in the system are transferred to the device.
Then the cyclic data exchange of process data and value status starts.
2.5
Device profiles
Introduction
Device profiles are defined for IO-Link to standardize access of the CPU user program to the
devices.
Data structure, data contents and basic functionality are defined in the device profiles. A
standard user view and an identical program access is thus achieved for a number of different
devices that have the same device profile.
IO-Link profiles
The device profile "Smart Sensor Profile" is currently defined for IO-Link. This profile is
especially suited for measurement sensors. In other words, measured values are transmitted
in addition to switching points.
In addition, the switchgear (for example, contactors) support the LVSG (Low Voltage
Switchgear) profile defined in IEC 61915-2.
2.6
IODD and Port Configuration Tool - S7-PCT
Device description IODD
An electronic device description, the IODD file (IO Device Description) is available for each
device. The IODD provides a wealth of information for system integration:
• Communication properties
• Device parameters with value range and default value
• Identification, process and diagnostic data
• Device data
• Text description
• Image of the device
• Manufacturer logo
The structure of the IODD is identical for all devices from all manufacturers. The structure of
the IODD is always represented in the identical manner by the IO-Link Configuration Tool of
the master manufacturer (for Siemens, S7-PCT). This ensures that the handling is the same
for all IO-Link devices regardless of the manufacturer.
Two different IODD versions are available for devices that support both V1.0 and V1.1
functionality.
15
System overview
2.6 IODD and Port Configuration Tool - S7-PCT
IO-Link system
Function Manual, 07/2022, A5E31637677-AC
