Emerson Liebert NX 50 and 60 Hz - Manual (Page 63)

UPS Multi-Module Installation
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3.4.4 Control 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 34.
Figure 34 Connections of a typical dual bus system utilising Load Bus Synch
3.4.5 Extended 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 and one on the Liebert NX UPS. In
this situation, the other UPS system 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
Example shown with ring control cables (“8”) for DSB applied to two 1+1 paralleled systems.
NOTE
Extended DBS interface box is also used for extending DBS cable length up to 150 metres for
DBS configuration between two groups of NX UPS systems.
UPS
X1-1 X1-2
X2-2 X2-1
Parallel Board
X4
X3 P5
P3
P4
P1 P2
X1-1 X1-2
X2-2 X2-1
Parallel Board
X4
X3 P5
P3
P4
P1 P2
8
X1-1 X1-2
X2-2 X2-1
Parallel Board
X4
X3 P5
P3
P4
P
1
P2
X1-1 X1-2
X2-2 X2-1
Parallel Board
X4
X3 P5
P3
P4
P
1
P2
8
UPS
B Parallel System I Parallel System II
DBS Cable
A