Siemens SIMATIC NET CP 343-1 ERPC Manual page 89

Process image
The process image is a special memory area in the programmable logic controller. At the
start of the cyclic program, the signal states of the input modules are transferred to the
process input image. At the end of the cyclic program, the process output image is
transferred as a signal state to the output modules.
Protocol
A set of rules for transferring data. Using these rules, both the formats of the frames and the
data flow are specified.
RJ-45
Symmetrical connector for data cables. It is also known as a Western plug. Widely used
connector used with telephone and ISDN technology; it is also used in LAN installations in
both office and industrial environments.
S7 subnet ID
You will find detailed information on this topic in the STEP 7 online help.
Server
A server is a device, or in general terms, an object that provides certain services. A service
is started at the instigation of a → client.
Services
Services provided by a communication protocol
SNMP
Simple Network Management Protocol: A protocol of the Internet protocol family for
monitoring, controlling and managing network nodes
Station
A station is identified by a
● MAC address in the Ethernet network
● PROFIBUS address in the PROFIBUS network.
Subnet
A subnet is part of a -> network whose parameters (for example -> PROFIBUS) must be
matched. The subnet includes bus components and all the attached stations. Subnets can,
for example, be connected together by → gateways to form a network.
A → system consists of several subnets with unique → subnet numbers. A subnet consists of
several → stations with unique → PROFIBUS or MAC addresses (Industrial Ethernet).
CP 343-1 ERPC
Manual, 03/2010, C79000-G8976-C239-02
Glossary
89