Operator controls and operating modes of the CPU 410-5H 
  7.1 Operating modes of the CPU 410-5H 
CPU 410-5H Process Automation/CPU 410 SMART 
System Manual, 10/2013, A5E32631667-AA 
93 
 
STARTUP mode 
Startup types  
The CPU 410 distinguishes between two startup types: cold restart and warm restart.  
●  During a cold restart, all data (process image, bit memory, timers, counters and data 
blocks) is reset to the start values stored in the program (load memory), regardless of 
whether they were configured as retentive or non-retentive. 
●  The associated startup OB is OB 102 
●  Program execution is restarted from the beginning (OB 102 or OB 1). 
●  A warm restart resets the process image and the non-retentive bit memories, timers, 
times, and counters. 
Retentive flags, times and counters retain their last valid value. 
All data blocks assigned the "Non Retain" attribute are reset to the downloaded values. 
The other data blocks retain their last valid value. 
●  The associated startup OB is OB 100 
●  Program execution is restarted from the beginning (OB 100 or OB 1). 
●  If the power supply is interrupted, the warm restart function is only available in backup 
mode. 
Special features in redundant mode 
The special features described below apply to startup when you operate two CPUs 410 
redundantly. 
Startup processing by the master CPU  
The startup system state is always processed by the master CPU in redundant mode. 
During STARTUP, the master CPU compares the existing I/O configuration with the 
hardware configuration that you created in STEP 7. The master CPU reacts as described 
above if there is a discrepancy. 
The master CPU checks and assigns parameters for the following: 
●  the switched I/O devices 
●  its assigned one-sided I/O devices