Configuring The Operation Of The Cpu And Modules - Siemens SIMATIC S7-1200 Manual

Easy to create the device configuration

5.5 Configuring the operation of the CPU and modules

5.5 Configuring the operation of the CPU and modules
To configure the operational parameters for the CPU, select the CPU in the Device view and
use the "Properties" tab of the inspector window.
Configuring the STOP-to-RUN operation of the CPU
Whenever the operating state changes from STOP to RUN, the CPU clears the process
image inputs, initializes the process image outputs, and processes the startup OBs.
(Therefore, any read accesses to the process-image inputs by instructions in the startup OBs
will read zero rather than the current physical input value.) To read the current state of a
physical input during startup, you must perform an immediate read. The startup OBs and any
associated FCs and FBs are executed next. If more than one startup OB exists, each is
executed in order according to the OB number, with the lowest OB number executing first.
The CPU also performs the following tasks during the startup processing.
● Interrupts are queued but not processed during the startup phase
● No cycle time monitoring is performed during the startup phase
● Configuration changes to HSC (high-speed counter), PWM (pulse-width modulation), and
PtP (point-to-point communication) modules can be made in startup
● Actual operation of HSC, PWM, and point-to-point communication modules only occurs in
RUN
After the execution of the startup OBs finishes, the CPU goes to RUN mode and processes
the control tasks in a continuous scan cycle.
Use the CPU properties to configure how the CPU starts up after a power cycle.
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You can configure the following CPU properties:
• PROFINET IP address and time
synchronization for the CPU
• Startup behavior of the CPU following an OFF-
to-ON power transition
• Local (on-board) digital and analog I/O, high-
speed counters (HSC), and pulse generators
• System clock (time, time zone and daylight
saving time)
• Read/write protection and password for
accessing the CPU
• Maximum cycle time or a fixed minimum cycle
time and communications load
• Web server properties
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Manual, 03/2014, A5E02486774-AF