Is it possible to use S7 controls as router to access the secondary controls which are in different subnets?


Yes, for this you can use the option "Activate S7 routing" in ibaPDA.

S7 routing is defined as the possibility to use S7 controls as router to access the secondary controls which are in different subnets. This also includes changing the bus system (Ethernet/Profibus/MPI).
The "S7 routing" function is not to be confused with "IP routing".
The following constellation is to clarify this:

The engineering computer (also with ibaPDA) is to access the CPU412 control. The computer and the control system are not directly connected with each other via a joint network/bus. The connection is to take place via the CPU314C controller.
"Forwarding" the communication in this controller is called "S7 routing".
In this example, the engineering computer and CPU314C are also in two different (logical) subnets. For a communication connection, an (IP) router needs to be used. This is completely independent of the "S7 routing" function and is not to be confused with it.

Example for S7 Routing'
The figure below shows the access from a PG to PROFIBUS via Ethernet.

Requirements for S7 Routing

  • The CPUs, CMs and CPs support routing.
  • All the devices using the gateway must receive information about which subnets can be reached via which routes (= routing information). The devices receive the routing information through downloading the hardware configuration in the CPUs.
    In the case of a topology with several subnets you must keep to the following order when downloading: First you download the hardware configuration into the CPU(s), which are connected to the same subnet as the PG/PC; then you download the CPUs of the other subnets one after the other starting with the nearest subnet through to the most distant

 

 

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