Siemens SIMATIC S7-1500 System Manual page 319

Basics of program execution
10.1 Programming the S7-1500R/H
As of firmware version V3.1:
• Switch R/H-CPU to STOP mode and assign the backup CPU role (Mode 11).
With this function, you can switch an R/H-CPU to STOP mode and assign the backup CPU
role. Requirement: Pairing must not be present.
This is required if the redundant system is in a non-defined state, for example when both
redundancy connections were interrupted at the same time and both R/H-CPUs have taken
on the role of primary CPU. You can find more information in section Failure of both
redundancy connections with S7-1500R at an interval ≤ 1 500 ms (Page 204) and in
section Failure of both redundancy connections with S7-1500R at an interval ≤ 55 ms
(Page 210).
After the instruction is called with Mode 11, the redundant system is in a defined state
again: Primary CPU in RUN mode and backup CPU in STOP mode.
Note
Only switch one R/H-CPU to STOP mode with the function; otherwise, the redundant
system switches to the STOP system state.
With the "RH_GetPrimaryID" instruction, you read out the redundancy ID of the primary
CPU in the user program. e.g. to always stop the R/H-CPU with the redundancy ID 1.
With the R-CPUs, the function is supported as of article number 6ES7513-1RM03-0AB0,
6ES7515-2RN03-0AB0.
• Allow SYNCUP with open PROFINET ring (Mode 14)
"RH_GetPrimaryID" instruction
You can use the "RH_GetPrimaryID" instruction in the user program to read out which CPU is
currently the primary CPU (see Determining the primary CPU with "RH_GetPrimaryID"
(Page 332) section for more information).
OB 72 (CPU redundancy error)
In addition to the OBs of the S7-1500 CPU, you can also use OB 72 (CPU redundancy error).
The operating system of each CPU of an R/H-system calls up the CPU redundancy error OB
(OB72) when one of the following events occurs:
• Loss of redundancy due to a CPU failure
• Loss of redundancy due to a CPU transition to STOP mode (triggered by the user or the
system)
Up to firmware version V2.8:
• The R/H system has entered the RUN-Redundant system state.
As of firmware version V2.9:
• The R/H-system has entered RUN-Redundant system state and the synchronization of the
two R/H-CPUs is possible redundantly.
• The R/H-system has entered RUN-Redundant system state, but the synchronization of the
two R/H-CPUs is not possible redundantly.
318
S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF