Johnson Controls METASYS NU-XBN101-0 Technical Manual page 13

If the (-) line is daisy chained as a single common (Figure 7), consistency
between (-) and (+) wires must be maintained. Also, 18 AWG (maximum)
wire must be used where the two (-) wires insert under a single terminal.
Figure 7: Wiring Contacts Using a Single Common (Daisy Chained)
Use the paired-wire technique (Figure 8), and not the daisy chained
scheme, when connecting to various, widely spaced devices, since a
single, widely spaced common may create a loop (antenna) effect and
induce significant transient noise onto the system.
Figure 8: Wiring Contacts Using Paired Wires
18 AWG
Termination
or smaller
(-)
_
(+)
+
_
(+)
+
_
(+)
+
xbn5
Termination
(-)
_
(+ )
+
(-)
_
(+ )
+
(-)
_
(+ )
+
xbn6
Point Multiplex Modules—Multiplex Binary
XM
Board
Binary
Input 1
Binary
Input 2
Binary
Input 3
XM
Board
Binary
Input 1
Binary
Input 2
Binary
Input 3
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