York DC180 Installation Manual page 53

Table 22: Simplicity SE UCB Details (Continued)
J15
FC+
FC–
COM
SHLD
EOL
switch
EOL
FC BUS
ISO PWR
Johnson Controls Unitary Products
Description
Factory wired SA Bus connector
Optional communication sub-board at center of UCB
Terminal FC BUS connections on left edge of the communication board
FC ("Field Connected") BUS BACnet MSTP
communication
FC ("Field Connected") BUS BACnet MSTP
communication
Common for the FC ("Field Connected") BUS
BACnet MSTP communication circuit
Shield for the FC ("Field Connected") BUS
BACnet MSTP communication circuit
Item Selector in red housing at left on top edge of the communication board
End Of Line selector switch for the FC BUS
BACnet MSTP communication circuit
LEDs on the communication board
Green End Of Line indicator
Green FC bus communication transmission
indicator
Green communication board Isolated Power
indicator
Function & Comments
Positive of the VDC (typically, a fluctuating 1.5 to 3.5 volts
reading to COM; at least 0.25 volts higher than –) FC bus
BACnet MSTP communication circuit
Positive of the VDC (typically, a fluctuating 1.5 to 3.5 volts
reading to COM; at least 0.25 volts lower than +) FC bus
BACnet MSTP communication circuit
Negative of the VDC FC bus BACnet MSTP communication
circuit
Earth ground reference of the cable to prevent interference on
the FC bus BACnet MSTP communication circuit
ON selected only for the UCB that is the terminus of the FC bus
BACnet MSTP communication cable to prevent signal "bounce-
back"
Lit indicates the EOL switch is selected ON
Lit/flickering indicates outgoing UCB FC bus communication is
currently active, off indicates the UCB is awaiting incoming FC
bus communication
Lit indicates the UCB is supplying power to the communication
sub-board
5120416-XIM-C-0216
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