Siemens SIMATIC ET 200AL System Manual page 1209

Glossary
IP address
To allow a PROFINET device to be addressed as a device on Industrial Ethernet, this device
also requires an IP address that is unique within the network. Example: An IPv4 address
consists of 4 decimal numbers with the value range 0 to 255. The decimal numbers are
separated by periods.
The IP address is made up of the following components:
● Address of the network
● Address of the device (generally called the host or network node).
IRT
IRT is a synchronized communication protocol for cyclic exchange of IRT data between
PROFINET devices. A reserved bandwidth is available in the send cycle for IRT data. The
reserved bandwidth ensures that the IRT data can be transferred at reserved synchronized
intervals, without being influenced also by higher other network loads (such as TCP/IP
communication, or additional real-time communication).
LAN
Local Area Network - a local network to which multiple computers within a company are
connected. The LAN therefore has a limited geographical span and is only available to the
company or institution.
Line depth
Designates the number of external switches or integrated switches interconnected in series.
MAC address
Worldwide unique device identification for all Ethernet devices. It is assigned by the
manufacturer and has a 3-byte vendor ID and 3-byte device ID as a consecutive number.
Every PROFINET device is assigned a worldwide unique device identifier at the factory. This
6-byte long device identifier is the MAC address.
Maintenance Required / Maintenance Demanded
A "Maintenance required" system message can be defined for different wear parameters and
an inspection of a component can be recommended, for example, when a certain number of
operating hours has elapsed.
The "Maintenance demanded" alarm is sent when the part involved needs to be replaced
within a foreseeable period.
(Example printer: The maintenance demanded alarm is sent when the ink/printer cartridges
have to be replaced immediately.)
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PROFINET with STEP 7 V15
Function Manual, 12/2017, A5E03444486-AH