Remote Rack Sensor Wiring
Liebert
®
CRV
™
140
13.0 R
EMOTE
R
ACK
S
ENSOR
W
IRING
Three 2T sensors come standard with each Liebert CRV (both 600mm and 300mm models). The
Liebert CRV is capable of supporting up to ten (10) 2T remote rack temperature sensors. It is
recommended that one (1) 2T housing be attached to each rack the Liebert CRV is intended to cool.
The sensors provide feedback directly to the cooling unit to improve efficiency and performance. Rack
sensors help combat cooling problems related to recirculation air, uneven rack loading and air
distribution. The 2T rack sensors are intended for cold aisle use only.
While installing the rack sensors is optional, Emerson recommends that they be installed.
Installations with multiple Liebert CRV cooling units should be connected in a Unit-to-Unit (U2U)
Ethernet network to leverage all of the Liebert iCOM
®
control benefits.
A sensor network can be extended at any time by connecting additional 2T sensors to the last 2T
temperature and humidity sensor on the network. Sensors connect in a daisy chain fashion back to
the cooling unit; individual wires from each sensor to the cooling unit are avoided.
There are four steps to setting up a remote rack sensor:
• Determine the location of sensors and mounting. See
• Set the DIP switches of the remote rack sensor must be configured to have a unique ID. See
Sections
through
• Route the CANbus cables and make the connections at the CRV and 2T sensors mounted on the
racks. See Sections
through
.
• Configure the Liebert iCOM—Control must be set to use the remote rack sensor as either a
controlling sensor or as a reference sensor. See
13.8 Remote Rack Sensor Operation and
.
Figure 122 2T rack sensor
13.1 DIP Switch Settings
Three 2T sensor housings are included with each Liebert CRV. The DIP switches in these sensors
have been preset at the factory. It is recommended that you confirm that the DIP switches have been
set correctly using the below table. Any additional 2T sensor housings will need their DIP switches
set per the below table. If the dip switches are not set correctly, the control will not operate properly.
Figure 123 DIP switches in 2T sensors
Temperature Sensing Probe
Back View
Front View
2T Sensor
1-5/8"
(41mm)
Max Depth
1-5/8" (41mm)
Each temperature
probe wire is
6 feet (1830mm)
long
3/16"
(4.5mm)
3-3/8"
(86mm)
4-7/16"
(112mm)
2-5/8"
(67mm)
DPN001983
Rev. 1
Switch Up = ON
Switch Down = OFF