Siemens SIMATIC S7-1500 System Manual page 267

• The CPU processes the startup OBs in the order of the startup OB numbers. The CPU
processes all programmed startup OBs regardless of the selected startup type (Figure
"Setting the startup behavior").
• If a relevant event occurs, the CPU can start the following OBs in startup:
– OB 82: Diagnostics interrupt
– OB 83: Removal/insertion of modules
– OB 86: Rack error
– OB 121: Programming error (only for global error handling)
– OB 122: I/O access error (only for global error handling)
All other OBs are started by the CPU only at the transition to the operating state RUN or
system state RUN-Redundant (OB 70).
Behavior when expected and actual configurations do not match
The configuration downloaded to the CPU is the expected configuration. The actual
configuration is the actual, physical configuration of the automation system. If the expected
configuration and actual configuration differ, the hardware compatibility setting defines the
behavior of the CPU.
Aborting or not running startup
If errors occur during startup, the CPU aborts STARTUP and returns to the STOP operating
state.
The CPU does not perform STARTUP under the following conditions:
• You have not inserted a SIMATIC memory card or an invalid one is inserted.
• You have not downloaded a hardware configuration to the CPU.
Configuring startup behavior
You configure the behavior of the CPU in STEP 7 in the "Startup" group of the CPU properties.
Proceed as follows to set the startup behavior:
1. Select the CPU in the device view of the STEP 7 hardware network editor.
2. In the properties, select the "Startup" area.
S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD
You can find a description of how to use global and local error handling in the STEP 7
online help.
Commissioning
11.4 Operating and system states
267