Siemens SIMATIC S7-1500 System Manual page 370

Redundancy IDs 1 and 2
Redundant operation is only possible if the two CPUs have different redundancy IDs. The
redundancy IDs can have values of 1 and 2. The CPUs save the redundancy IDs in their
retentive data areas.
Both CPUs have redundancy ID 1 in the following cases:
• Default setting upon initial commissioning
• After reset to factory settings
In the STEP 7 project tree, each of the two CPUS is displayed with its own tree. The
redundancy ID is used to assign a project tree to the real CPU in STEP 7. The upper CPU of the
two CPUs in the project tree always has a redundancy ID of 1. The lower CPU of the two
always has a redundancy ID of 2.
Diagnostics displays are assigned to the real CPUs in the project tree in the same way.
Figure 12-2 Assignment of the redundancy IDs between project tree and real configuration
Assigning redundancy IDs to CPUs in the configuration
Requirement: The CPUs have the same firmware version and the same article numbers.
You have the following options for assigning different redundancy IDs to the CPUs:
• Automatic assignment
• Assignment using the display
S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF
Commissioning
12.3 Commissioning procedure
369