Siemens SIMATIC ET 200AL, System Manual

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Glossary
Communication
Function Manual, 05/2021, A5E03735815-AJ
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Duplex
Data transmission system; a distinction is made between full and half duplex.
Half duplex: One channel is available for alternate data exchange (sending or receiving
alternately but not at the same time).
Full duplex: Two channels are available for simultaneous data exchange in both directions
(simultaneous sending and receiving in both directions).
End-entity certificate
→ See also device certificate
Ethernet
International standard technology for local area networks (LAN) based on frames. It defines
types of cables and signaling for the physical layer and packet formats and protocols for
media access control.
Ethernet network adapter
Electronic circuitry for connecting a computer to an Ethernet network. It allows the exchange
of data / communication within the network.
FETCH/WRITE
Server services using TCP/IP, ISO-on-TCP and ISO for access to system memory areas of S7
CPUs. Access (client function) is possible from a SIMATIC S5 or a third-party device/PC. FETCH:
Read data directly; WRITE: Write data directly.
Field device
→ Device
Freeport
Freely programmable ASCII protocol; here for data transfer via a point-to-point connection.
FTP
F ile T ransfer P rotocol; a network protocol for transferring files via IP networks. FTP is used to
download files from the server to the client or to upload files from the client to the server.
FTP directories can also be created and read out and directories and files can be renamed or
deleted.
HMI
H uman M achine I nterface, device for visualization and control of automation processes.