Siemens SIMATIC ET 200AL, System Manual

Page: 1558 / 2255

Glossary
Communication
Function Manual, 05/2021, A5E03735815-AJ
437
Redundant systems
Redundant systems have multiple (redundant) instances of key automation components.
Process control is maintained if a redundant component fails.
Ring topology
All devices of a network are connected together in a ring.
Root CA certificates
→ See also root certificate
Root certificate
This is the certificate of a certificate authority: It signs end-entity certificates and intermediate
CA certificates with its private key.
The "Subject" attribute and the "Issuer" of this certificate must be identical. This certificate
authority has signed its certificate itself.
The "CA" field must be set to "True".
TIA Portal V14 has such a root CA certificate:
If you configure the OPC UA server of an S7-1500 in the TIA Portal, the TIA Portal generates
an end-entity certificate for the OPC UA server and signs that certificate with its own private
key.
The signature of this end-entity certificate can be verified with the public key of the TIA
Portal. This key can be found in the root CA certificate of the TIA Portal.
Router
Network node with a unique identifier (name and address) that connects subnets together
and allows transportation of data to uniquely identified communications nodes in the
network.
RS232, RS422 and RS485
Standard for serial interfaces.
RTU
Modbus RTU (RTU: R emote T erminal U nit, transfers the data in binary form; allows a good
data throughput. The data must be converted to a readable format before it can be
evaluated.
S7 routing
Communication between S7 automation systems, S7 applications or PC stations in different
S7 subnets via one or more network nodes functioning as S7 routers.