Siemens Simatic S7-300 CPU 31xC and CPU 31x S7-300 - Manual (Page 18)

Operating and display elements
2.1 Operating and display elements: CPU 31xC
CPU 31xC and CPU 31x, Technical data
2-2
Manual, Edition 08/2004, A5E00105475-05
The figure below illustrates the integrated digital and analog I/Os of the CPU with open front
covers.
SF
BF
DC5V
FRCE
RUN
STOP
RUN
STOP
MRES
X11 X12
2
2 1 3
1 2 3
Figure 2-1 Integrated I/Os of CPU 31xC (CPU 314C-2 PtP, for example)
The figure shows the following integrated I/Os
(1) Analog I/Os
(2) each with 8 digital inputs
(3) each with 8 digital outputs
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.