Chapter 3 Deployment CPU 21x Manual VIPA CPU 21x
3-14 HB103E - Rev. 05/45
Operating modes
The CPU can be in one of 3 operating modes:
• STOP
• START-UP
• RUN
Certain conditions in the operating modes START-UP and RUN require a
specific reaction from the system program. In this case the application
interface is often provided by a call to an organization block that was
included specifically for this event.
• Processing of the application program has stopped.
• If the program was being processed, the values of counters, timers,
flags and the contents of the process image are retained during the
transition to the STOP mode.
• Outputs are inhibited, i.e. all digital outputs are disabled.
• RUN-LED off
• STOP-LED on
• During the transition from STOP to RUN a call is issued to the start-up
organization block OB 100. The length of this OB is not limited. The
processing time for this OB is not monitored. The start-up OB may issue
calls to other blocks.
• All digital outputs are disabled during the start-up, i.e. outputs are
inhibited.
• RUN-LED blinks
• STOP-LED off
When the CPU has completed the start-up OB, it assumes the operating
mode RUN.
• The application program in OB 1 is processed in a cycle. Under the
control of alarms other program sections can be included in the cycle.
• All timer and counters being started by the program are active and the
process image is updated with every cycle.
• The BASP-signal (outputs inhibited) is deactivated, i.e. all digital outputs
are enabled.
• RUN-LED on
• STOP-LED off
Outline
Operating mode
STOP
Operating mode
START-UP
Operating mode
RUN
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