Optimize The Cabling Of The Ports - Siemens SIMATIC ET 200AL System Manual

Functions
5.12 Accelerating startup
5.12.5

Optimize the cabling of the ports

Requirements
You have made the following settings for the port in question to reduce the startup time of
the IO device:
● Fixed transmission rate
● Autonegotiation deactivated
The time for negotiating the transmission rate during startup is saved.
If you have disabled autonegotiation, you must observe the cabling rules.
Properties of ports
PROFINET devices have the following two types of ports:
Type of port
Switch port with crossed pin assignment
Terminal device port with normal pin assign-
ment
Crossed pin assignment means that the pin assignment for the ports for sending and
receiving between the respective PROFINET devices is inverted internally.
Validity of the cabling rules
The cabling rules described in the following paragraph apply exclusively for the situation in
which you have specified a fixed port setting in STEP 7.
Rules for cabling
You can connect several IO devices in series using patch cables. To do this, connect port 2
of the IO device (distributed I/O) with port 1 of the next IO device. The following graphic
provides an example with two IO devices.
Figure 5-99 Optimized cabling for accelerated startup
256
PROFINET devices
For IO devices: Port 2
For S7-CPUs with two ports: Ports 1 and 2
For IO devices: Port 1
For S7-CPUs with one port: Port 1
Function Manual, 12/2017, A5E03444486-AH
PROFINET with STEP 7 V15