Crestron electronic infiNET EX CEN-RFGWX-EX - Manual (Page 32)

InfiNET EX™ Gateway Crestron CEN-RFGW-EX
When calculating the length of wire for a particular Cresnet run, the wire
gauge and the Cresnet power usage of each network unit to be connected
must be taken into consideration. Use Crestron Certified Wire only. If
Cresnet units are to be daisy-chained on the run, the Cresnet power usage
of each network unit to be daisy-chained must be added together to
determine the Cresnet power usage of the entire chain. If the unit is
home-run from a Crestron system power supply network port, the
Cresnet power usage of that unit is the Cresnet power usage of the entire
run. The wire gauge and the Cresnet power usage of the run should be
used in the following equation to calculate the cable length value on the
equation’s left side.
Cable Length Equation
L = Length of run (or chain) in feet
R = 6 Ohms (Crestron Certified Wire: 18 AWG (0.75 MM ))
or 1.6 Ohms (Cresnet HP: 12 AWG (4 MM ))
P = Cresnet power usage of entire run (or chain)
2
2
L <
40,000
R x P
Where:
Make sure the cable length value is less than the value calculated on the
right side of the equation. For example, a Cresnet run using 18 AWG
Crestron Certified Wire and drawing 20 watts should not have a length of
run more than 333 feet (101 meters). If Cresnet HP is used for the same
run, its length could extend to 1250 feet (381 meters).
NOTE: All Crestron certified Cresnet wiring must consist of two
twisted pairs. One twisted pair is the +24V conductor and the GND
conductor and the other twisted pair is the Y conductor and the Z
conductor.
Strip and Tin
Wire When daisy-chaining Cresnet units, strip the ends of the wires carefully
to avoid nicking the conductors. Twist together the ends of the wires that
share a pin on the network connector and tin the twisted connection.
Apply solder only to the ends of the twisted wires. Avoid tinning too far
up the wires or the end becomes brittle. Insert the tinned connection into
the Cresnet connector and tighten the retaining screw. Repeat the
procedure for the other three conductors.
Add Hubs Use of a Cresnet Hub/Repeater (CNXHUB) is advised whenever the
number of Cresnet devices on a network exceeds 20 or when the
combined total length of Cresnet cable exceeds 3000 feet (914 meters).
28 • infiNET EX™ Gateway: CEN-RFGW-EX Operations & Installation Guide – DOC. 6706A