Siemens SIMATIC ET 200AL, System Manual

Page: 1512 / 2255

Communication
Function Manual, 05/2021, A5E03735815-AJ
391
Connection resources
12
12.1 Connection resources of a station
Introduction
Some communications services require connections. Connections occupy resources in the
automation system (station). The connection resources are made available to the station by
the CPUs, communications processors (CPs) and communications modules (CMs).
Connection resources of a station
The connection resources available depend on the CPUs, CPs and CMs being used and must
not exceed a maximum number per station.
The maximum number of resources of a station is determined by the CPU.
Reserved connection resources
Each CPU has reserved connection resources for PG, HMI and Web server communication.
This ensures, for example, that a PG can always establish at least one online connection with
the CPU regardless of how many other communications services are already using connection
resources.
Dynamic connection resources
In addition, dynamic resources exist. The difference between the maximum number of
connection resources and the number of reserved connection resources is the maximum
number of dynamic connection resources.
The communication services PG Communication, HMI Communication, S7 Communication,
Open User Communication, Web Communication, OPC UA Client/Server Communication and
other communication from the pool of dynamic connection resources are used.