Siemens SIMATIC PCS 7 CPU 410-5H

Failure and replacement of components during redundant operation
11.2 Failure and replacement of components of the distributed I/Os
CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB
197
11.2.3
Failure and replacement of a PROFIBUS DP slave
Starting situation
Failure
How does the system react?
The S7-400H is in redundant system state and a
DP slave fails.
Both CPUs signal the event in the diagnostics
buffer and via a corresponding OB 86.
Procedure
Proceed as follows to replace a DP slave:
Step
What to do?
How does the system react?
1 Turn off the supply for the DP slave. With one-sided I/O: OB 86 and OB85 are
called for access errors during the PA up-
date.
With switched I/O: OB70 is called (incoming
event), the LED REDF lights up.
2
Remove the bus connector.
–
3
Replace the DP slave.
–
4 Plug the bus connector back in and turn the
power supply back on.
• The CPUs process the rack failure OB
86 synchronously (outgoing event).
• With switched I/O: OB70 is called (out-
going event), the LED REDF goes out.
• The associated DP master can address
the DP slave.