Siemens SIMATIC ET 200AL, System Manual

Page: 1863 / 2255

PROFINET with the redundant S7-1500R/H system
6.5 Main differences between IO device with S2 system redundancy and standard IO device
PROFINET with STEP 7
298
Function Manual, 05/2021, A5E03444486-AL
Influence changeover time of switched S1 devices
As of FW version V2.9, you can influence the changeover time between disconnection and
return of switched S1 devices after a failure/STOP of the primary CPU.
Advantages:
•
Optimization of the changeover time between disconnection and return of switched S1
devices
• Prioritization of the return of S1 devices in the PROFINET ring by setting a lower
changeover time for S1 devices with important process functions.
The changeover time depends on the watchdog timer of the switched S1 device. The
watchdog timer is the product of the update time multiplied by the accepted update cycles
without IO data. With the parameters, you influence the time as of which the new primary
CPU starts returning the S1 device. The return also depends on the amount of time that is
required for the parameter assignment of the S1 device.
You set the parameters in STEP 7 in the properties of the interface of each S1 device:
•
Update time: Advanced options > Real time settings > IO cycle > Update time
• Watchdog timer: Advanced options > Real time settings > IO cycle > Watchdog timer >
Accepted update cycles without IO data
Setting a shorter changeover time of an S1 device: Reduce the values of the parameters/of a
parameter.
Setting a longer changeover time of an S1 device: Increase the values of the parameters/of a
parameter.
6.5 Main differences between IO device with S2 system redundancy
and standard IO device
Table 6- 1 Main differences between IO device with S2 system redundancy and standard IO device
Property IO device with S2 system redun-
dancy
Standard IO device
Requirement for IO device Device supports S2 system redun-
dancy
-
Maximum simultaneously supported
ARs with regard to the same modules
2 1
Behavior when replacing the primary
CPU
Continuous connection with S7-
1500R/H redundant system
Process data is transferred further.
Temporary disconnection from S7-1500R/H
redundant system.
No process data is transferred until the
standard IO device is available again. The
status of the outputs depends on the substi-
tute value behavior of the respective chan-
nels.