Accelerating Startup; Options For Accelerating The Startup Of Io Devices - Siemens SIMATIC ET 200AL System Manual

5.12

Accelerating startup

5.12.1

Options for accelerating the startup of IO devices

Reducing the startup time of IO devices
The time needed for the startup of IO devices depends on various factors and can be
reduced in different ways.
You can achieve a significant reduction in the startup time using the "Prioritized startup"
PROFINET function.
To further reduce the startup times, use the following measures in addition to the "Prioritized
startup":
● Optimize the port settings
● Optimize the cabling of the ports
● Perform measures in the user program (for docking systems only)
These measures will accelerate the startup of IO devices even without "Prioritized startup".
However, you can only achieve the fastest startup times of about 500 ms by combining all
the measures with "Prioritized startup".
Note
Startup time up to 8 s
In the following situation, despite prioritized startup, a startup time of up to 8 s may occur:
On a docking point, multiple physical IO devices dock as an IO device with identical device
names and identical IP configurations (for example, docking point for automatic transport
system).
Dependencies
The length of the startup time for an IO device (distributed I/O) with the "Prioritized startup"
PROFINET function depends on the following factors:
● IO devices (distributed I/O)
● IO structure of the IO device (distributed I/O)
● Modules of the IO device (distributed I/O)
● IO controller
● Switch
● Port setting
● Cabling
PROFINET with STEP 7 V15
Function Manual, 12/2017, A5E03444486-AH
Functions
5.12 Accelerating startup
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