User manual

Operation
49 Liebert
®
iCOM
®
for Liebert DSE
™
3.8 CANbus Connections Between the Liebert DSE, Liebert EconoPhase
™
and Liebert
MC
™
Communication between the Liebert DSE, Liebert EconoPhase and Liebert MC condenser is achieved
using a terminal screw CANbus connection. CANbus (Controller Area Network bus) communication
to each device is wired as a daisy chain using a shielded, twisted pair cable. The guidelines below
must be followed to ensure reliable communication.
Application Length
• The CANbus cable between the Liebert DSE and all outdoor equipment should be no longer than
350 ft. (107m).
Field-Supplied Cable Specification
• Conductors: 22-18AWG stranded, tinned copper
• Twisted pair (minimum eight twists per foot)
• Braided shield or foil shield with drain wire
• Low capacitance (15pF/FT or less)
• UL-approved temperature rated to 167°F (75°C)
• UL-approved voltage rated to 300V
• UV-resistant and moisture-resistant if not run in conduit.
• Plenum-rated NEC type CMP, if required by national or local codes.
• Examples Belden 89207 (plenum-rated), or Alpha Wire 6454
Installation
• Shield must always be wired to ground at the indoor unit.
• Do not run the CANbus cable in the same conduit, raceway or chase as high-voltage wiring.
• 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.
• Avoid running the CANbus cables by devices that might introduce noise, such as machines,
fluorescent lights and electronics.
• Avoid stretching cables.
• Separate CANbus wires from high-voltage wires and other high-voltage sources by 12 inches
(305mm).
A CANbus cable must be connected from the Liebert DSE at the designated terminal blocks in the
electric panel (terminal block 49-1, 49-2, SH) to the Liebert MC
™
condenser board (TB49). If there is
an additional condenser, TB50 of the first condenser must be connected to TB49 on the second
condenser.
Systems equipped with a Liebert EconoPhase require an additional CANbus cable connected from
TB50 on the last condenser board to TB49 in the Liebert EconoPhase. There are two boards inside
dual-pump Liebert EconoPhase systems. In dual-pump systems, the two internal boards are
connected with factory wiring. The field connection in these units must be made at a separate
terminal block labeled TB49.
A CANbus connection between a Liebert MC and a Liebert EconoPhase is polarity sensitive.
The last device in the CANbus chain must be terminated. To terminate the Liebert MC or Liebert
EconoPhase, a jumper must be placed on J6, Pins 1 and 2. When the device is not last, the CANbus
termination jumper must be placed on J6, Pins 2 and 3. Refer to Figure 40 and the Liebert DSE user
manual, SL-18925, for additional information on CANbus connections.