Mode Selector - Siemens SIMATIC S7-400 Reference Manual

Structure of a CPU 41x
1.4

Mode Selector

Function of the Mode Selector
Using the mode selector, you can put the CPU in RUN/RUN-P or STOP mode or
reset the memory of the CPU. STEP 7 offers further options for changing the
mode.
Positions
The mode selector switch is designed as a keyswitch. Figure 1-5 illustrates the
possible positions of the mode selector.
Figure 1-5
Table 1-2 explains the positions of the mode selector. In the event of a fault or if
there are startup problems, the CPU will go into or remain in STOP mode
irrespective of the position of the mode selector.
1-14
RUN-P
RUN
STOP
MRES
Positions of the Mode Selector
Automation System S7-400 CPU Specifications
A5E00165965-01