Siemens SIMATIC PROFINET Function Manual page 254

Glossary
Twisted-pair
Fast Ethernet via twisted-pair cables is based on the IEEE 802.3u standard (100 Base-TX).
The transmission medium is a shielded 2x2 twisted-pair cable with an impedance of 100 Ω
(AWG 22). The transmission characteristics of this cable must meet the requirements of
category 5.
The maximum length of the connection between the terminal and the network component
must not exceed 100 m. The connectors are designed according to the 100Base-TX
standard with the RJ45 connector system.
Update time
An IO device / IO controller in the PROFINET IO system is supplied cyclically with new data
from the IO controller / IO device within this time interval. The update time can be configured
separately for each IO device and determines the interval at which data is sent from the IO
controller to the IO device (outputs) as well as from the IO device to the IO controller
(inputs).
User program
In SIMATIC, we distinguish between the CPU operating system and user programs. The
user program contains all instructions, declarations and data by which a plant or process can
be controlled. The user program is assigned to a programmable module (for example, CPU,
CM) and can be structured in smaller units.
WAN
A network that extends beyond LAN boundaries and enables, for example, intercontinental
network communication. Legal rights do not belong to the user but to the provider of the
communication network.
XML
XML (Extensible Markup Language) is a flexible, easy to understand and easy to learn data
description language. Information is exchanged using readable XML documents. These
include continuous text supplemented by structure information.
254
PROFINET with STEP 7 V14
Function Manual, 09/2016, A5E03444486-AG