Siemens IM 155-6 PN ST Equipment Manual page 16

Product overview
2.2 Functions
Note
BusAdapter BA 2xMA12 and firmware 4.1
When using a BA 2xMA12 BusAdapter and firmware 4.1, note that an update to version V4.2
via another BusAdapter must first be performed to make the IM executable.
Cabling with fixed connection setting
If you set a fixed connection setting of the port in STEP 7, you must also disable
"Autonegotiation/Autocrossover".
You can find more information on this topic in the STEP 7 online help and:
• As of STEP 7 V12 in the PROFINET with STEP 7 V13
(http://support.automation.siemens.com/WW/view/en/49948856) function manual
• As of STEP 7 V5.5 in the PROFINET System Description
(http://support.automation.siemens.com/WW/view/en/19292127) system manual
Isochronous real-time communication
Synchronized transmission method for cyclic exchange of IRT data between PROFINET
devices. A reserved bandwidth within the send clock is available for IRT data. The reserved
bandwidth ensures that the IRT data is also transmitted in time-synchronized intervals,
unaffected by other high network loading (e.g. TCP/IP communication or additional real time
communication).
A topological configuration is required for IRT.
Note
IO controller as sync master with IRT communication
We recommend operating the IO controller also as a sync master when configuring the IRT
communication.
Otherwise, IRT- and RT-configured IO devices may fail if the sync master fails.
You can find more information on the configuration of synchronized PROFINET devices in
sync domains in the STEP 7 online help and:
• As of STEP 7 V12 in the PROFINET with STEP 7 V13
(http://support.automation.siemens.com/WW/view/en/49948856) function manual
• As of STEP 7 V5.5 in the PROFINET System Description
(http://support.automation.siemens.com/WW/view/en/19292127) system manual
Prioritized startup
Prioritized startup is a PROFINET IO function in a PROFINET IO system with IRT and RT
communication. It reduces the time needed for correspondingly configured IO devices to
return to cyclic user data exchange.
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IM 155-6 PN ST interface module (6ES7155-6AU01-0BN0)
Equipment Manual, 10/2020, A5E03576904-AE