Siemens CP 343-1 Manual page 22

Performance data
2.5 PROFINET IO characteristic data
Configuration limits of the CP as a PROFINET IO device and I-device
The CP supports the following configuration if it is configured as a PROFINET IO device and
as an I-device:
Table 2- 7
Characteristic
Size of the transfer area
Number of transfer areas
Size of the user data
The size of the user data is calculated from the maximum frame size (gross 548 bytes)
minus the following values: 1 for the CP itself, 1 per Interface, 1 per port, 1 for each plugged-
in module in HW Config or per slot used.
Table 2- 8
* By using fewer but larger modules, the amount of user data can be increased.
Execution times of the FC blocks PNIO_SEND / PNIO_RECV
The execution time required to process the function blocks (PNIO_SEND, PNIO_RECV)
required on the S7-300 CPU is decisive for the calculation of the reaction times in
PROFINET IO.
Note
Measurements of transmission and reaction times in Ethernet, PROFIBUS and PROFINET
networks for a series of configurations can be found on the Internet at the following address:
25209605 (http://support.automation.siemens.com/WW/view/en/25209605)
22
Configuration limits of the CP as a PROFINET IO device
Example of calculating the user data 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 *
Value
240 bytes
32
Manual, 12/2018, C79000−G8976−C201-08
CP 343-1