Liebert Essential Installation Guide for Dual Bus Configurations in NX UPS Systems

UPS Multi-Module Installation

3.4.4Control Wires

For Liebert NX to NX dual bus configuration, interconnect the optional DBS cable between any DBS ports of two parallel systems as illustrated in Figure 19.

Figure 19 Connections of a typical dual bus system utilising Load Bus Synch

	UPS
Parallel Board		Parallel Board
X3	P5	X3	P5
	X4		X4
X2-2 X2-1		X2-2 X2-1
P2	P1	P2	P1
X1-1 X1-2		X1-1 X1-2
P3	P4	P3	P4
8
	Parallel System I		A

		UPS
	Parallel Board		Parallel Board
	X3	P5	X3	P5
		X4		X4
DBS Cable	X2-2 X2-1		X2-2 X2-1
	P2	P1	P2	P1
	X1-1 X1-2		X1-1 X1-2
	P3	P4	P3	P4
	8
		Parallel System II		B

NOTE

Example shown with ring control cables ("8") for DSB applied to two 1+1 paralleled systems.

3.4.5Extended Dual Bus Synchronization Option (DBS Interface Box)

For Liebert NX to non- NX (whether another Liebert UPS range or not) dual bus configuration, one DBS interface box shall be mounted on the non- Liebert NX UPS. In this situation, the other UPS sys- tem is always treated as a master and the following conditions are covered:

•Master and slave are both on inverter

•Master on bypass, slave on inverter

NOTE

Extended DBS interface box is also used for extending DBS cable length up to 150 meters (490ft) for DBS configuration between two groups of NX UPS systems.

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