Connecting   
6.2 Connecting the 24 V DC power supply 
  SIMATIC IPC427C 
34  Operating Instructions, 04/2009, A5E02414743-01 
6.2  Connecting the 24 V DC power supply 
To be noted before you connect the device 
Note the following in order to operate the device safely and according to regulation: 
 
WARNING 
 
The device should only be connected to a 24V DC power supply which satisfies the 
requirements of safe extra low voltage (SELV).  
If the device is used on a wall, in an open rack or other similar locations, an NEC Class 2 
current source is required in order to meet the UL requirements (UL 60950-1). In all other 
cases (IEC / EN / DIN EN 609501) either a current source of limited output (LPS = Low 
Power Source), or a line-side fuse or a line-side circuit breaker is necessary. The power 
needs to be limited to a value below 4.16 A. The fuse value required: Max. 4 A. 
Use the special plug supplied to connect the supply voltage. Connect the PE conductors as 
described in the next section. 
 
NOTICE 
 
The permitted cable cross-section for the 24 VDC connection is 0.75 mm
2 
to 2.5 mm
2
.    
 
NOTICE 
 
If a CompactFlash card is used in the device, make sure that the card is seated correctly 
before you connect it. 
 
Connecting 
 
Steps for connecting the device to the 24 V DC power supply 
1.  Switch off the 24 V DC power source. 
2.  Connect the power supply using the plug 
(included in the package). 
3.  Connect the PE conductor. 
 
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