Siemens Simatic S7-300 CPU 31xC and CPU 31x S7-300 User Manual
Page 171
Technical data of CPU 31x
7.2 CPU 312
CPU 31xC and CPU 31x, Technical data
Manual, Edition 08/2004, A5E00105475-05
7-5
Technical data
Number of function modules and communication
processors you can operate
•
FM
Max. 8
•
CP (PtP)
Max. 8
•
CP (LAN)
Max. 4
Time-of-day
Real-time clock
Yes (SW clock)
•
Buffered
No
•
Accuracy
Deviation per day < 15 s
•
Behavior of the realtime clock after POWER
ON
The clock keeps running, continuing at the time-
of-day it had when power was switched off.
Operating hours counter
1
•
Number
0
•
Value range
2
31
(if SFC 101 is used)
•
Granularity
1 hour
•
Retentive
Yes; must be manually restarted after every
restart
Clock synchronization
Yes
•
In the PLC
Master
•
On MPI
Master/slave
S7 signaling functions
Number of stations that can be logged on for
signaling functions
6
(depends on the number of connections
configured for PG / OP and S7 basic
communication)
Process diagnostics messages
Yes
•
Simultaneously enabled interrupt S blocks
Max. 20
Testing and commissioning functions
Status/control variables
Yes
•
Variables
Inputs, outputs, memory bits, DBs, timers,
counters
•
Number of variables
–
Of those as status variable
–
Of those as control variable
30
30
14
Forcing
Yes
•
Variables
Inputs, outputs
•
Number of variables
Max. 10
Block status
Yes
Single step
Yes
Breakpoints
2
Diagnostic buffer
Yes
•
Number of entries (not configurable)
Max. 100