Siemens SIMATIC S7-300 Series

CPUs
1-10
PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP
A5E00111190-01
1.1.6 Clock and Runtime Meter
Table 1-5 shows the characteristics and functions of the clock for the various
CPUs.
When you assign parameters to the CPU in STEP 7, you can also set functions
such as synchronization and the correction factor(see the STEP 7 online help
system).
Table 1-5 Characteristics of the Clock of the CPUs
Characteristics
312 IFM 313 314 314 IFM 315 315-2 DP 316-2DP 318-2
Type Software clock Hardware clock (integrated “real-time clock”)
Manufacturer
setting
DT#1994-01-01-00:00:00
Backup Not possible  Backup battery
 Accumulator
Operating hours
counter
Number
Value range
- 1
0
0 to 32767 hours
8
0 to 7
0 to 32767
hours
Accuracy
 with switched
on power
supply
0 to 60 C
 with switched
off power
supply
0C
25C
40C
60C
... max. deviation per day:
9s
+2s to -5s
2s
+2s to -3s
+2s to -7s