Technical Specifications

Designing a Liebert XD Solution
46
Plan wiring runs for U2U communication when designing the layout of the conditioned space. In
addition to following general good wiring practices, take these precautions:
• Keep control and communication cables away from power cables to prevent electromagnetic
interference.
• Do not bend cables to less than four times the diameter of the cable.
• Do not deform cables when securing them in bundles or when hanging them.
• Keep cables away from devices that can introduce noise into them, such as machines, fluorescent
lights and electronics.
• Avoid stretching cables; tension when pulling cables should not exceed 25 pounds (11kg) of
pulling tension.
• Do not secure cables with any method that might damage them. Use approved hangers, such as
those for telephone wire or RG-6 coaxial cable, available at most hardware stores.
3.27.2 CANbus Cable Length in a Network
The maximum total length of cable that can be used in a CANbus network differs by the type of
Liebert XD cooling module as shown in Table 23.
Figure 44 Single daisy chain of Liebert XDO smart modules in CANbus network
The cumulative length of cable used in the example in Figure 44
is 134 ft. (40.8m), far shorter than
the maximum allowable cable run of 580 ft. (177m) for Liebert XDV10 modules.
Table 23 Allowable total CAN cable length
Module
Allowable Total CAN
Cable Length, ft (m)
Liebert XDV8 580 (177)
Liebert XDV10 580 (177)
Liebert XDO16 590 (180)
Liebert XDO20 590 (180)
Liebert XDH20 580 (177)
Liebert XDH32 585 (178)
* The internal CANbus cable within the Liebert XD module and the remote sensors has been accounted for.
Table 24 Cumulative cable length in Figure 44
Cable
Segments
Length of Each
ft. (m)
Cumulative Length
ft. (m)
14 6 (1.8) 84 (25.6)
1 20 (6) 20 (6)
1 30 (9.1) 30 (9.1)
Combined cable length
134 (40.8)
Liebert
XDP
Liebert
XDO
Liebert
XDO
Liebert
XDO
Liebert
XDO
Liebert
XDO
Liebert
XDO
Remote
Sensor A
Liebert
XDO
Liebert
XDO
Rack Rack Rack Rack Rack RackRack Rack Rack Rack Rack
Rack Rack Rack Rack Rack RackRack Rack Rack Rack Rack
Remote
Sensor B