Interspace Industries TheatreCue 16 Way V4 System - 16 Outstations - Manual (Page 24)

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24.
Outstation Cables
There are literally hundreds of different cable types that are
suitable for use with the Cue Light system.
The two primary cable characteristics of interest for the Cue
Light application are wire size and cable capacitance.
(Continued)
The size of the copper wire in a cable determines the
voltage drop on that cable. Larger copper wires decrease
the voltage drop and allow for longer cable runs with more
Outstations connected.
The size of the copper wire is measured in either cross
sectional area such as square mm or by wire gauge such
as AWG (American Wire Gauge). Bigger AWG numbers
represent smaller wires. 24 AWG is the smallest size that
should be used with 18-22 AWG being preferable. The
actual wire size required for an installation will depend on
the length of the cable runs and the maximum number of
Outstations to be connected to each run.
The screen provides the return path for the
Outstation’s power. A screen with low resistance is preferred.
A woven copper screen usually has lower resistance than a
wrapped foil screen.
Characteristic Impedance (measured in ohms) is a
common cable specification. It can be ignored in this
application. It is not a measure of a cable’s resistance.
If many Outstations are placed on the end of a cable run that
is either very long and/or very thin, there may be excessive
voltage drop for the Outstations to keep working normally.
Rather than stop working due to the lack of voltage, the
Outstations automatically dim their lamps to reduce power
consumption and hence reduce the voltage drop.
Lower cable resistance = longer possible cable runs due to
lower voltage drop.
A following table (see page 28) gives a guide as to wire size
Vs length Vs number of Outstations that can be connected
to each cable run.
cable’s
Wire Size
Where the total cable length is:-
less than 500m (1640 ft)
greater than 500m
18-22 AWG cables with core to core capacitance
of less than 80pF/m (24pF/ft) should be selected.
Suitable cables include:-
24 AWG: Belden 9501, 9841
Alphawire 5471C
20 AWG: Belden 9463
Standard XLR microphone cable or virtually any
1 pair 24AWG screened cable can be used.
(1640 ft)
A brief cable guide