5
SFB-PN-IRT-8M12-IOP
Operating instructions
Safety fieldbox
EN
4. Electrical connection
4.1 General information for electrical connection
To supply the safety fieldbox, M12 power connectors, cables with a
cross-section of max. 1.5 mm² can be connected to the fieldbox.
The electrical connection may only be carried out by
authorised personnel in a de-energised condition.
4.2 Power supply and fuse protection
Secure the supply voltage of the safety fieldbox with a 10 A fuse. In
order to increase the cable cross section for the supply voltage of the
fieldbox, both connections from Us and GND must be connected in
parallel. Pins 1 + 4 and 2 + 3 in the fieldbox are bridged.
0 VDC
+24 VDC
Power
10A
BN
1
BK
4
3
2
BU
WH
SFB
1
4
3
2
I Power O
GND
GND
Us
Us
4.3 Internal fuse elements device ports
The device ports X0 - X7 are designed for 0.8 A continuous current
and equipped in each case with an auto-resettable fuse of 1.5 A for line
protection. If the fuse element is triggered, the red LED on the device
port flashes with 4 pulses.
After eliminating the overload at one of the device ports, the fuse resets
itself after a short cool-down phase.
X0 – X7
1
2
A1
1,5A
8
...
4.4 Earth concept and shielding
A functional earth is connected for fault-free operation of the safety
fieldbox. Earth loops must be avoided when connecting the functional
earth.
The FE functional earth is normally connected via the switch. In the
event of EMC problems, the fieldbox can be earthed via the separate
FE connection.
An earth strap is available as an accessory.
Wiring examples for avoidance of earth loops:
FE
SFB
P1
P2
Ethernet
FE
SPS /
Switch
FE
SFB
P1
P2
Ethernet
PLC /
FE
SFB
P1
P2
Ethernet
FE
SPS /
Switch
FE
SFB
P1
P2
Ethernet
PLC /
