Siemens SIMATIC S7-1500 System Manual page 304

For more information on DNA redundancy and the parameter assignment of the lower-level
PROFINET ring on the Y switch, refer to the SCALANCE XB-200/XC-200/XF-200BA/XP-200/XR-
300WG Web Based Management
(https://support.industry.siemens.com/cs/ww/en/view/109780061) Configuration Manual.
Note
Special features when configuring the PROFINET interfaces
When using S2/S1 devices downstream of a Y switch, all IP addresses must be in the same
subnet. S2/S1 devices have only one interface module in contrast to R1 devices. If the current
primary CPU is in a different subnet than the S2/S1 devices, these are no longer accessed by
the primary CPU. In this case, STEP 7 already outputs an error message when compiling the
configuration.
Application example with Y-switches and DNA redundancy
Under the following link
(https://support.industry.siemens.com/cs/ww/de/view/109816704/en), you will find an
application example with Y-switches and DNA redundancy, showing scenarios in line and ring
topologies.
Line topology configuration with R1 devices and switches
Reparameterize the operating mode of the switches
The default operating mode IO device (S2) of the switches permanently triggers the MAINT
diagnostics at the H-CPUs. The MAINT LEDs on the H-CPUs light up. To prevent MAINT
diagnostics, change the operating mode of the switches from "IO device(S2)" to "IO
device(S1)". The parameter operating mode can be set in STEP 7 in the "I/O communication"
view for each IO device.
See also
Configuring R/H CPUs (Page 289)
S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF
9.5 Configuring additional topologies
Configuration
303