5.12 Operating modes
5.12.1
Overview
The CPU can be in one of 4 operating modes:
n
Operating mode STOP
n
Operating mode START-UP
n
Operating mode RUN
n
Operating mode HOLD
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.
n
The application program is not processed.
n
If there has been a processing before, the values of counters, timers, flags and the
process image are retained during the transition to the STOP mode.
n
Outputs are inhibited, i.e. all digital outputs are disabled.
n
RUN-LED off
n
STOP-LED on
n
During the transition from STOP to RUN a call is issued to the start-up organization
block OB 100. The processing time for this OB is not monitored. The START-UP OB
may issue calls to other blocks.
n
All digital outputs are disabled during the START-UP, i.e. outputs are inhibited.
n
RUN-LED
blinks as soon as the OB 100 is operated and for at least 3s, even if the start-up time
is shorter or the CPU gets to STOP due to an error. This indicates the start-up.
n
STOP-LED off
When the CPU has completed the START-UP OB, it assumes the operating mode RUN.
n
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.
n
All timers and counters being started by the program are active and the process
image is updated with every cycle.
n
The BASP-signal (outputs inhibited) is deactivated, i.e. all digital outputs are enabled.
n
RUN-LED on
n
STOP-LED off
The CPU offers up to 3 breakpoints to be defined for program diagnosis. Setting and
deletion of breakpoints happens in your programming environment. As soon as a break-
point is reached, you may process your program step by step.
For the usage of breakpoints, the following preconditions have to be fulfilled:
n
Testing in single step mode is possible with STL. If necessary switch the view via
‘View
è
STL’
to STL.
n
The block must be opened online and must not be protected.
1.
Activate
‘View
è
Breakpoint Bar’
.
2.
Set the cursor to the command line where you want to insert a breakpoint.
Operating mode STOP
Operating mode START-
UP
Operating mode RUN
Operating mode HOLD
Precondition
Approach for working with
breakpoints
System 300S
+
Deployment CPU 315-4PN23
Operating modes > Overview
HB140 | CPU | 315-4PN23 | en | 18-02
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