Table 2-3 Positions Of The Mode Selector Switch - Siemens Simatic S7-300 Technical Data Manual

Operating and display elements
2.2 Operating and display elements: CPU 31x
Slot for the SIMATIC Micro Memory Card (MMC)
A SIMATIC Micro Memory Card (MMC) is used as memory module. You can use MMCs as
load memory and as portable storage medium.
Note
These CPUs do not have an integrated load memory and thus require an MMC for
operation.
Mode selector switch
The mode selector switch is used to set the CPU operating mode.
Table 2-3
Position
RUN
STOP
MRES
Reference
• CPU operating modes:
• Information on CPU memory reset:
• Evaluation of the LEDs upon error or diagnostic event:
Power supply connection
Each CPU is equipped with a double-pole power supply socket. The connector with screw
terminals is inserted into this socket when the CPU is delivered.
2-6
Positions of the mode selector switch
Meaning
RUN mode
STOP mode
CPU memory reset
Commissioning, Commissioning Modules, CP Memory Reset by means of Mode Selector
Switch
and CPU 31x, Test Functions, Diagnostics and Troubleshooting, Diagnostics with the
help of Status and Error LEDs
Description
The CPU executes the user program.
The CPU does not execute a user program.
Mode selector switch position with pushbutton function for CPU
memory reset. A CPU memory reset by means of mode
selector switch requires a specific sequence of operation.
STEP 7 Online Help
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Operating instructions CPU 31xC and CPU31x,
Operating Instructions CPU 31xC
CPU 31xC and CPU 31x, Technical data
Manual, Edition 08/2004, A5E00105475-05