Determining The Primary Cpu With "Rh_Getprimaryid - Siemens Simatic S7-1500R System Manual

Basics of program execution
7.4 Special instructions for S7-1500R/H redundant systems
Reference
You can find additional information on the "RH_CTRL" instruction in the STEP 7 online help.
You can find more information on SYNCUP in the section SYNCUP system state
(Page 205).
7.4.2

Determining the primary CPU with "RH_GetPrimaryID"

You use the "RH_GetPrimaryID" instruction to read out which CPU is currently the primary
CPU. The instruction outputs the redundancy ID of the primary CPU at the Ret_Val block
parameter.
Figure 7-4
Example: Reading maintenance information from the SIMATIC memory card of the primary CPU
Proceed as follows to read specific maintenance information from the SIMATIC memory card
of the primary CPU:
1. Get the redundancy ID of the primary CPU with "RH_GetPrimaryID".
2. Read the maintenance information from the SIMATIC memory card of the primary CPU
with "GetSMCInfo".
– If the CPU with redundancy ID 1 is the primary CPU, enter "12" at the Mode block
– If the CPU with redundancy ID 2 is the primary CPU, enter "22" at the Mode block
Reference
You can find more information on the "RH_GetPrimaryID" instruction in the STEP 7 online
help.
160
"RH_GetPrimaryID" instruction
parameter ("1" for redundancy ID, "2" for maintenance information).
parameter ("2" for redundancy ID, "2" for maintenance information).
S7-1500R/H redundant system
System Manual, 10/2018, A5E41814787-AA