Siemens Simatic S7-300 CPU 31xC and CPU 31x S7-300 User Manual
Page 19
Operating and display elements
2.1 Operating and display elements: CPU 31xC
CPU 31xC and CPU 31x, Technical data
Manual, Edition 08/2004, A5E00105475-05
2-3
Mode selector switch
Use the mode selector switch to set the CPU operating mode.
Table 2-1
Positions of the mode selector switch
Position
Meaning
Description
RUN
RUN mode
The CPU executes the user program.
STOP
STOP mode
The CPU does not execute a user program.
MRES
CPU memory
reset
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.
Reference
•
CPU operating modes:
STEP 7 Online Help.
•
Information on CPU memory reset:
Operating instructions CPU 31xC and CPU31x,
Commissioning, Commissioning Modules, CPU Memory Reset by means of Mode
Selector Switch
•
Evaluation of the LEDs upon error or diagnostic event:
Operating Instructions CPU 31xC
and CPU 31x, Test Functions, Diagnostics and Troubleshooting, Diagnostics with the
help of Status and Error LEDs
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.
Differences between the CPUs
Table 2-2
Differences of the CPUs 31xC
Element
CPU
312C
CPU
313C
CPU
313C-2 DP
CPU
313C-2 PtP
CPU
314C-2 DP
CPU
314C-2 PtP
9-pole DP
interface (X2)
–
–
X
–
X
–
15-pole PtP
interface (X2)
–
–
–
X
–
X
Digital inputs
10
24
16
16
24
24
Digital outputs 6
16
16
16
16
16
Analog inputs –
4 + 1
–
–
4 + 1
4 + 1
Analog outputs –
2
–
–
2
2
Technological
functions
2 counters 3 counters 3 counters 3 counters
4 counters
1 channel for
positioning
4 counters
1 channel
for
positioning