Siemens Simatic S7-300 CPU 31xC and CPU 31x S7-300 - Manual (Page 187)

Technical data of CPU 31x
7.5 CPU 315-2 PN/DP
CPU 31xC and CPU 31x, Technical data
Manual, Edition 08/2004, A5E00105475-05
7-21
Technical data
Assembly
Racks
Max. 4
Modules per rack 8
Number of DP masters
•
Integrated 1
• via CP 2
Number of function modules and communication processors you can operate
•
FM Max. 8
• CP (PtP) Max. 8
• CP (LAN) Max. 10
Time-of-day
Real-time clock
Yes (hardware clock)
• Factory setting DT#1994-01-01-00:00:00
• Buffered Yes
• Buffered period Typically 6 weeks (at an ambient temperature of
104 °F)
• Behavior of the clock on expiration of the
buffered period
The clock keeps running, continuing at the time-
of-day it had when power was switched off.
• Behavior of the realtime clock after POWER
ON
The clock continues running after POWER OFF.
• Accuracy Deviation per day: < 10 s
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/slave
• On MPI Master/slave
S7 signaling functions
Number of stations that can be logged on for
signaling functions
16
(depends on the number of connections
configured for PG / OP and S7 basic
communication)
Process diagnostics messages Yes
• Simultaneously enabled interrupt S blocks 40
Testing and commissioning functions
Status/control variables
Yes
• Variables Inputs, outputs, memory bits, DBs, timers,
counters