46 Series Installation and User Guide V1.0
24
Options and Additional Information
Control of music source and level
via external DC
It may be necessary in some installations to adjust the music
level and select music source in one or more zones from an
external AV control system. If the REMOTE MUSIC CONTROL
PORTS are not required for RL-1/RSL-6 Series remote control
plates, they may be used to receive DC voltages from the
external system to effect these adjustments.
Both music source selection and level can be controlled over
their full ranges with a DC voltage of 0 to +3.3 V. The pinout
of each REMOTE MUSIC CONTROL PORT is as follows:
PIN USE
1 0 V ref.
2 Music level control (0 to +3.3 V)
3 Music source selection (0 to +3.3 V)
NOTE: If the control voltage source is not isolated from the
power earth, there is a small risk of creating a ‘ground loop’
by linking the mixer technical ground (0 V) to the ground
(0 V) of the equipment supplying the control voltages. To
minimise this risk, we suggest that all pieces of equipment be
in close proximity, and supplied from the same power outlet.
Music level
Music level in a zone may be varied over its full range by
applying a DC voltage of between 0 V and +3.3 V to pin 2,
the 0 V reference being connected to Pin 1. 0 V on pin 2
corresponds to maximum level and +3.0 V will produce 90
dB of attenuation. The rate of attenuation is approximately
33 mV/dB.
Note that there is an internal 1k “pull-up” resistor between
pin 2 and the internal +3.3 V rail. If pin 2 is left “oating”, this
pull-up will result in full attenuation. The output impedance
of the control voltage source should be low enough to
overcome the effect of this resistor.
Music source
Music source for a zone may be controlled by applying
various DC voltages of between 0 and +3.3 V to pin 3, the
0 V reference being connected to pin 1. A voltage of between
+1.5 v and +1.8 V at pin 3 will select Line input 1 and one of
0.17 V or less will select Line input 6. The other line inputs will
be selected with intermediate voltages. Taking pin 3 above
+2 V will deselect all inputs, making the zone effectively ‘off’
for music.
The table below lists the DC voltages required at pin 3 to
select each line input. The third column is the value of a
resistor which should be connected between pins 1 and 3 to
permanently ‘force’ a zone to a particular line input.
INPUT DC VOLTAGE RESISTOR VALUE*
OFF 3.3 v Open-circuit
Line 1 1.71 v 16k2
Line 2 1.37 v 10k7
Line 3 1.0 v 6k8
Line 4 0.69 v 4k02
Line 5 0.35 v 1k8
Line 6 0 v Short-circuit
* resistors from the IEC E96 range (±1%) are recommended
Note that there is an internal 15k “pull-up” resistor between
pin 3 and the internal +3.3 V rail. If pin 3 is left “oating”, this
pull-up will cause ‘OFF’ to be selected. The output impedance
of the control voltage source should be low enough to
overcome the effect of this resistor.
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