Configuration of the CPU 410 
  3.2 CPU 410 monitoring functions 
CPU 410 Process Automation/CPU 410 SMART 
System Manual, 05/2017, A5E31622160-AC 
39 
 
CPU 410 monitoring functions 
Monitoring functions and error messages  
The hardware of the CPU and operating system provide monitoring functions to ensure 
proper operation and defined reactions to errors. Various errors may also trigger a reaction 
in the user program. 
The table below provides an overview of possible errors and their causes, and the 
corresponding responses of the CPU. 
Additional test and information functions are available in each CPU; they can be initiated in 
STEP 7. 
 
Module failure (SM, FM, CP) 
Time error 
•  The user program execution time (OB 1 and all interrupts and 
error OBs) exceeds the specified maximum cycle time. 
•  OB request error 
•  Overflow of the start information buffer 
•  Time-of-day error interrupt 
INTF 
Power supply module(s) 
fault (not power failure) 
In the central or S7-400 expansion rack 
•  at least one backup battery of the power supply module is com-
pletely discharged. 
•  the backup battery voltage is missing. 
•  the 24 V supply to the power supply module has failed. 
EXTF 
Diagnostic interrupt  An I/O module with interrupt capability reports a diagnostic interrupt 
The synchronization module signals a diagnostic interrupt; see 
Chapter Synchronization modules for the CPU 410. (Page 239)  
The LED EXTF lights up with the first incoming diagnostic interrupt 
and goes out with the outgoing diagnostic interrupt. 
EXTF 
 
Swapping interrupt  Removing or inserting a module as well as inserting an incorrect 
module type. 
Removing a synchronization module. 
EXTF 
Redundancy error 
•  Loss of redundancy on the CPUs 
•  Redundancy loss/ station failure of a switched DP station 
•  Failure of a DP master 
•  Redundancy loss/station failure of a switched IO device 
REDF 
CPU hardware fault 
•  A memory error was detected and eliminated 
INTF 
Program execution error 
•  Priority class is called, but the corresponding OB is not availa-
ble. 
•  In the event of an SFB call: Missing or faulty instance DB 
•  Process image update error 
INTF 
EXTF