Remote Rack Sensor Wiring
Liebert
®
CRV
™
148
13.6 Route the CANbus Wire into the Cooling Unit-300mm (12")
Connecting the CANbus sensors will require working in the high-voltage electrical compartment of
the Liebert CRV. Emerson recommends having installation performed by a properly trained and
qualified electrician.
A 2T Sensor Terminal is factory-installed in the Liebert CRV 300mm (12") unit's electric panel section
(see
). This terminal is factory-wired to the Liebert iCOM on the front of the Liebert CRV.
The display comes “Terminated” from the factory and must be “Un-terminated' to allow connecting
additional sensors. See
for termination jumper location for front panel display and sensor
boards.
Connect a CANbus cable to the factory-installed 2T Sensor Terminal inside the 300mm (12") Liebert
CRV as shown in Top entry route the CANbus wire into the cooling unit-300mm (12") DX. Route the
CANbus cable out of the Liebert CRV to an external 2T Sensor Terminal and sensors on the racks as
shown in Top entry route the CANbus wire into the cooling unit-300mm (12") DX. See
and
for an example of arranging the sensor array.
Use additional CAN cables to connect the remaining 2T rack sensors to each other. Avoid using
excessive lengths of cable between sensors. The order in which the 2T temperature and humidity
sensors are attached does not matter. However, the last sensor connected must be set to “terminated.”
13.3 Terminating the Last 2T Sensor on a Network
for details.
!
WARNING
Arc flash and electric shock hazard. Can cause injury and death.
Disconnect all local and remote electric power supplies and wear appropriate personal
protective equipment per NFPA 70E before working within the electric control enclosures.
CANbus cabling will be near the Liebert CRV's main disconnect switch, which has high
voltage supply power. Some of the CANbus cabling must be done without a clear view of the
high-voltage wiring and contact with the high-voltage connections.
Before proceeding with installation, read all instructions, verify that all the parts are included
and check the nameplate to be sure the voltage matches available utility power.
The Liebert iCOM® microprocessor does not isolate power from the unit, even in the Unit Off
mode.
Some internal components require and receive power even during the Unit Off mode of the
Liebert iCOM control.
Install and open a remote disconnect switch and verify with a voltmeter that live hazardous
voltage potential is not present inside the unit cabinet before working within. Refer to the
unit electrical schematic.
Follow all national and local codes.