Siemens SIMATIC S7-1500 System Manual page 51

Unlike system redundancy S2, system redundancy R1 has a separate interface module for
each of the two ARs. Due to these redundant interface modules, the availability is higher than
with an S2 device.
• Behavior in RUN-Redundant system state:
The PROFINET communication runs on both system redundancy ARs simultaneously, each
between one of the CPUs (IO controller) and an interface module of the R1 device.
In the case of failure of an interface module of an R1 device, only the ARs switch over. The
roles of the H-CPUs do not change.
If, however, the primary CPU fails or is switched to STOP, the S7-1500H redundant system
then behaves as follows:
– The previous backup CPU becomes the new primary CPU.
– The new primary CPU uses the AR to the other interface module of the IO device and
– The AR between the previous primary CPU and the assigned interface module is
• Behavior in RUN-Solo system state:
Only the primary CPU is IO controller. PROFINET communication runs on the AR between
the primary CPU (IO controller) and the interface module of the IO device assigned to the
primary CPU. The backup CPU separates all its ARs.
In STEP 7 you configure an IO device with system redundancy R1 by:
• Connecting the left interface module of the R1 device to the H-CPU with redundancy ID 1.
• You have to connect the right interface module of the R1 device to the H-CPU with
redundancy ID 2.
Switched S1 device
As of FW version V2.8, the S7-1500R/H redundant system supports the "Switched S1 device"
function.
The "Switched S1 device" function of the CPU enables operation of standard IO devices on the
S7-1500R/H redundant system.
Standard IO devices are always assigned to both CPUs of the S7-1500R/H redundant system.
In contrast to an IO device with system redundancy S2, a standard IO device supports only
one AR.
As of FW version V3.0, the backup CPU of S7-1500H can establish an AR to an S1 device in a
line topology. The primary CPU then receives data via the backup CPU.
• Behavior in the RUN-Redundant system state:
The PROFINET communication runs on the AR between one of the CPUs (IO controller) and
the standard IO device.
If this is the primary CPU and it fails, the redundant S7-1500R/H system behaves as
follows:
– The AR between the primary CPU and the standard IO device is disconnected.
– The previous backup CPU becomes the new primary CPU.
– The S7-1500R/H redundant system temporarily has no access to the inputs and no
– The new primary CPU builds an AR to the standard IO device.
– As soon as the new primary CPU has set up the AR, the S7-1500R/H redundant system
S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD
still has access to the inputs and control over the outputs of the IO device.
disconnected.
control over the outputs of the standard IO device. The status of the outputs depends
on the substitute value behavior of the respective channels.
has access to the inputs again and control over the outputs of the standard IO device.
System overview
4.3 S7-1500 R/H-CPUs
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