Startup Mode - Siemens CPU 410-5H Process Automation System Manual

7.1.3

STARTUP mode

Startup types
The CPU 410 distinguishes between two startup types: cold restart and warm restart.
Cold restart
● During a cold restart, all data (process image, bit memory, timers, counters and data
● The associated startup OB is OB 102
● Program execution is restarted from the beginning (OB 102 or OB 1).
Warm restart
● A warm restart resets the process image and the non-retentive bit memories, timers,
● 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
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
CPU 410-5H Process Automation/CPU 410 SMART
System Manual, 10/2013, A5E32631667-AA
blocks) is reset to the start values stored in the program (load memory), regardless of
whether they were configured as retentive or non-retentive.
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.
mode.
Operator controls and operating modes of the CPU 410-5H
7.1 Operating modes of the CPU 410-5H
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