Technical data of CPU 31x 
  7.8 CPU 319-3 PN/DP 
CPU 31xC and CPU 31x, Technical Data 
Manual, 01/2006 Edition, A5E00105475-06 
7-43 
Technical data 
Analog channels   
•  Inputs 
4096 
•  Outputs 
4096 
•  Inputs, central 
256 
•  Outputs, central 
256 
Removal 
Racks, Max.  4 
Modules per rack, Max.  8 
Number of DP masters 
•  Integrated 
2 
•  Via CP 
4 
Operable function modules and communication 
processors 
 
•  FM 
8 
•  CP (PtP) 
8 
•  CP (LAN) 
10 
Time 
Clock   
•  Hardware clock 
Yes 
•  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   
•  Number 
4 
•  Number 
0 to 3 
•  Value range 
0 to 2 
31
 hours 
(using the SFC 101) 
•  Granularity 
1 hour 
•  Retentive 
Yes; must be manually restarted after every 
restart 
Time synchronization   
•  supported 
Yes 
•  In the AS 
Master/slave 
•  On MPI 
Master/slave 
•  on Ethernet via NTP 
Yes (as client) 
S7 message functions 
Number of stations that can be logged on for 
signaling functions 
32 
(depends on the number of connections 
configured for PG / OP and S7 basic 
communication)