Technical Data   
4.3 Clock 
  D4x5 
52  Manual, 03/2007 Edition 
4.3  Clock 
Features of real-time clock 
The following table contains the features and functions of the control unit clock.  
Table 4-9  Clock features 
Features  Meaning 
Type  Hardware clock (integrated "realtime clock") 
Default setting when delivered  DT#1994-01-01-00:00:00 
Accuracy 
With supply voltage on  
•  0 to 55° C 
With supply voltage off 
•  25° C 
•  -20° C to 70° C 
Max. deviation per day: 
 
•  ±9 s 
 
•  ±2 s 
•  +2 s to -9 s 
Backup time  Typically 5 days (at 0 to 25° C) 
Charging time   1 hr 
With power OFF 
In the power OFF state, the control unit clock continues to run during the the backup time 
(with the exception of the software clock). The buffer is recharged in the power ON state.  
An error message is output if the backup function is defective. With power ON, the clock 
resumes at the time set at the factory. 
When the control unit is reset to the factory settings, the clock is also reset to the "factory 
default setting."