Performance data
2.6 Characteristic data of the integrated switch
CP 343-1 Lean
Manual, 10/2012, C79000−G8976−C198−07
19
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)
2.6 Characteristic data of the integrated switch
Learning addresses / deleting addresses (aging time)
The switch integrated in the CP (PROFINET interface) reads the source addresses included
in the data packets. The switch therefore learns the addresses of the end devices connected
via a port.
If the switch receives a data packet, it directs this packet only to the port via which the
appropriate end node can be reached.
The switch monitors the age of the learned addresses. Addresses that exceed the "aging
time" are deleted. The aging time is 5 minutes.
Ports can be deactivated individually
The ports of the switch integrated in the CP can be deactivated individually in STEP 7 /
HW Config. This can, for example, be used for service purposes.
To do this, open the properties dialog of the relevant port and select the "disabled" setting
under "Options > Transfer medium / duplex".
The port is turned off completely when it is disabled. The corresponding LED on the device
(for example X1P1) is then turned off.
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