Siemens SIMATIC ET 200AL - Page 937

Glossary
Communication
Function Manual, 12/2017, A5E03735815-AF
251
Modbus TCP
T
ransmission
C
ontrol
P
rotocol; Open communications protocol for Ethernet based on a
master/slave architecture. The data are transmitted as TCP/IP packets.
Network
A network consists of one or more interconnected subnets with any number of devices.
Several networks can exist alongside each other.
NTP
The
N
etwork
T
ime
P
rotocol (NTP) is a standard for synchronizing clocks in automation
systems via Industrial Ethernet. NTP uses the connectionless UDP transport protocol for the
Internet.
OPC UA
OPC
U
nified
Automation
is a protocol for communication between machines, developed by
the OPC Foundation.
Operating system
Software that allows the use and operation of a computer. The operating system manages
resources such as memory, input and output devices and controls the execution of
programs.
PG
→ Programming device
PNO
→ PROFIBUS user organization
Point-to-point connection
Bidirectional data exchange via communications modules with a serial interface between two
communications partners (and two only).
Port
Physical connector to connect devices to PROFINET. PROFINET interfaces have one or
more ports.