Siemens Simatic S7-300 CPU 31xC and CPU 31x S7-300 - Manual (Page 115)

Technical data of CPU 31xC
6.2 CPU 312C
CPU 31xC and CPU 31x, Technical data
Manual, Edition 08/2004, A5E00105475-05
6-5
Technical data
Assembly
Racks
Max. 1
Modules per rack Max. 8
Number of DP masters
• Integrated None
• Via CP Max. 1
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 < 10 s
• Behavior of the realtime clock after POWER
OFF
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 hours
(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
max. 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
Max. 30
Max. 30
Max. 14
Forcing Yes
• Variables Inputs, outputs
• Number of variables Max. 10