10 IIoT functionality
10.1 MQTT
There are the following domains:
Domain name
Definition
Example content
identity
All fixed data which is defined by the
used hardware and which cannot be
changed by configuration or at runtime.
Device name, ordering number, MAC
address, port types, port capabilites
and more.
config
Configuration data which is commonly
loaded once at startup, mostly by a
PLC.
IP address, port modes, input logic,
failsafe values and more.
status
All (non-process) data which changes
quite often in normal operation.
Bus state, diagnostic information, IO-
Link device status and data.
process
All process data which is produced and
consumed by the device itself or by
attached devices.
Digital inputs, digital outputs, cyclic IO-
Link data.
iold
IO-Link device parameters according to
the IO-Link specification.
Vendor name, product name, serial
number, hardware revision, software
revision and more.
Table 13: Data domains
There is often one topic used for all gateway related information and topics
for each port. All identity topics are published just once at start-up, because
this information should never change. All other topics are published either in
a fixed interval or just triggered manually, according to the configuration.
Manual EtherCAT®
Version 1.1 04/2021
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