Siemens SIMATIC ET 200SP - Page 213

Commissioning
11.6 Operating modes of the CPU
Distributed I/O system
212 System Manual, 09/2019, A5E03576849-AJ
No.
Operating mode transitions
Effects
③
STOP →
STARTUP
The CPU switches to "STARTUP" mode
if:
• The hardware configuration and
program blocks are consistent.
• You set the CPU to "RUN" mode via
the programming device and the
mode switch in is RUN position.
Or
• You set the mode switch from STOP
to RUN.
The CPU clears the non-retentive memory, and re-
sets the content of non-retentive DBs to the start
values of the load memory. Retentive memory and
retentive DB contents are retained.
The 500 newest entries in the diagnostics buffer are
retained.
④
STARTUP →
STOP
In the following cases, the CPU goes
from "STARTUP" to "STOP" mode
when:
• The CPU detects an error during
startup.
• You set the CPU to "STOP" via the
programming device or mode switch.
• The CPU executes a STOP com-
mand in the Startup OB.
These operating mode transitions have no effect on
data.
⑤
STARTUP →
RUN
In the following cases, the CPU goes
from "STARTUP" to "RUN" mode when:
• The CPU has initialized the PLC
tags.
• The CPU has executed the startup
blocks successfully.
⑥
RUN → STOP In the following cases, the CPU goes
from "RUN" back to "STOP" mode when:
• The CPU detects an error which
prevents further work.
• The CPU executes a STOP com-
mand in the user program.
• You set the CPU to "STOP" via the
programming device or mode switch.