Johnson Controls FIRE-MON-17, Technical Manual, Page: 42 / 72

42 IFC Networking—Metasys Intelligent Fire Network
Example 2
If the repeater feedthrough switch is set to the Off position (refer to
Figure 17), isolating the three FN segments on the right from the
FN segments on the left, separate ground fault detection circuits must be
fed through. The node second from the right continues to provide ground
fault detection up to the RPT-W Port B, and thus, must be an IFC panel.
The node on the far left of Figure 17 provides ground fault detection up to
the RPT-W Port A, and also must be an IFC panel.
node4
IFC Node
Node
IFC Node
Node
Power Supply
Ground Fault
Detection
Enabled
MIB-W
MIB-W
MIB-W
MIB-W
RPT-W
Off
SW2
On
SW3
SW1
Off
SW1
On
Ports B
A Ports B A
Twisted Pair
Wire
B Ports A
Twisted Pair
Wire
Ports A B
Ports A
B
SW1
Off
Power Supply
Ground Fault
Detection
Disabled Power Supply
Ground Fault
Detection
Enabled Power Supply
Ground Fault
Detection
Disabled
Figure 17: Bus (Example 2)
Note: On remotely powered nodes, ground fault detection is processed
through the main power supply (MPS-24A or MPS-24B). Ground
faults that occur on a remotely powered INA will be reported to the
network as a fault within the node containing the power supply.