Maximum frame size / volume of data for PROFINET IO devices - STEP 7

Communications modules and network components

ft:publication_title
Communications modules and network components
Product
STEP 7
Version
V20
Publication date
11/2024
Language
en-US
Maximum frame size / volume of data for PROFINET IO devices

Size of the user data with the CP 1616

The size of the user data (process data) is calculated from the maximum frame size (gross volume of data) minus the values for the modules plugged into this IO device. This results in the net volume of data.

Example of the calculation of the user data (bytes) of the CP 1616 as an IO device with homogeneous modules (for example only DI modules)

Bytes

Explanation

1434

Gross size of the frame

-16

for the maximum number of pluggable modules

= 1418

Net size of the user data

Example of the calculation of the user data (bytes) of the CP 1616 as an IO device with heterogeneous modules (for example DI/DO)

Bytes

Explanation

1434

Gross size of the frame

-32

for twice the maximum number of pluggable modules

= 1370

Net size of the user data

Size of the user data with the CP 343-1 (Lean/Standard/Advanced)

The size of the user data (process data) is calculated from the maximum frame size (gross volume of data) minus the values for the CP and the interface itself, for the number of ports and the modules plugged into this IO device. This results in the net volume of data.

Example of calculating the user data (bytes) of the CP 343-1 as an IO device

Bytes

Explanation

548

Gross size of the frame

-1

for the CP itself

-1

for the Interface

-2

for 2 ports

-32

for the maximum number of pluggable modules

= 512

Net size of the user data *