Stop Operating State; Run Operating State - Siemens SIMATIC S7-1500 System Manual

Commissioning
11.4 Operating states of the CPU
11.4.3

STOP operating state

Response
The CPU does not execute the user program in STOP.
All outputs are disabled or react according to the parameter settings for the relevant module:
They provide a configured substitute value or retain the last value output and thus keep the
controlled process in a safe operating state.
Points to note
The STOP operating state results in a frame failure at the drive with a corresponding
response at the drive end (for example, OFF3 fast stop, depends on parameter assignment).
You can find additional information in the SINAMICS S120 Communication function manual
(https://support.industry.siemens.com/cs/ww/de/view/109763284/en).
11.4.4

RUN operating state

Response
Cyclic, time-driven, and interrupt-driven program execution are performed in RUN.
Addresses in the "Automatic update" process image are automatically updated in each
program cycle. You can also find more information in Process images and process image
partitions (Page 106).
Execution of the user program
Once the CPU has written the outputs and read the inputs, it executes the cyclic program
from the first instruction to the last instruction. Events with a higher priority, such as
hardware interrupts, diagnostic interrupts, Motion Control functions and communication, can
interrupt the cyclic program flow and prolong the cycle time.
If you have configured a minimum cycle time, the CPU will not end the cycle until this
minimum cycle time has expired, even if the user program is completed sooner.
The operating system monitors the execution time of the cyclic program for a configurable
upper limit known as the maximum cycle time. You can restart this time monitoring at any
point in your program by calling the RE_TRIGR instruction.
If the cyclic program exceeds the maximum cycle time, the operating system will attempt to
start the time error OB (OB 80). If the OB does not exist, the CPU ignores the maximum
cycle time overshoot. If the cycle monitoring time is exceeded for a second time, for example
while the time error OB is being processed, the CPU switches to STOP.
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SIMATIC Drive Controller
System Manual, 11/2019, A5E46600094-AA