Limitation Of The Data Infeed Into The Network - Siemens SIMATIC ET 200AL System Manual

5.5.8

Limitation of the data infeed into the network

Limiting the data infeed into the network on PROFINET interfaces
The "Limit data infeed into the network" function limits the network load of standard Ethernet
communication which is fed into the network by the interface to a maximum value. This does
not apply to cyclic real-time communication (RT/IRT).
In a PROFINET IO system, critical network loads can occur quickly with standard Ethernet
communication, especially in line topologies. Devices which feed a lot of standard Ethernet
communication into the PROFINET IO system, should support the function "Limit data infeed
into the network". If necessary, you should optimize your topology by avoiding e.g. standard
Ethernet devices in line topologies. You can find additional information on this in section
Setup recommendations for optimizing PROFINET (Page 183).
Depending on the interface, you can activate or deactivate the "Limit data infeed into the
network" function. If you use the X1 interface of an S7-1500 CPU as the IO controller or I-
device, the "Limit data infeed into the network" function is always enabled. Example: If you
are not using the X1 interface of an S7-1500 CPU as IO controller or I-device, you can
enable or disable the function.
Uses of the limitation of the data infeed to the network
● Division of the bandwidth for standard Ethernet communication between devices:
In PROFINET networks cyclic real-time communication and standard Ethernet
communication share the same network. This means that only a limited bandwidth
remains for standard Ethernet communication. The limitation of the data infeed ensures
that the remaining bandwidth for standard Ethernet communication is not used just by
one device, but is divided between several devices.
● Smoothing peaks in the data infeed:
The limitation of the data infeed smooths peak loads of standard Ethernet communication
(for example, from Open User Communication, access by the Web server).
● Limiting problems in the data infeed:
If applications in a device generate too much data, this data is not forwarded to the
PROFINET network. Negative effects (for example data loss, communication breakdown)
remain limited to the device and its communications partner. Other nodes are not
disturbed.
PROFINET with STEP 7 V15
Function Manual, 12/2017, A5E03444486-AH
Functions
5.5 Real-time communication
187