Crown Audio IQ-MCA-IQ-MC8 - Manual (Page 21)

Page 21 Reference Manual
IQ-MC Modules
When wiring RJ-11 connectors, it is
good practice to follow the USOC
protocol for RJ-11 connector cable.
This protocol assigns wire colors as
follows:
1 white-green 4 white-blue
2 white-orange 5 orange-white
3 blue-white 6 green-white
When wiring RJ-45 connectors, it is
good practice to follow the EIA/TIA
568B protocol for RJ-45 connector
cable. This protocol assigns wire
colors as follows:
1 white-orange 5 white-blue
2 orange-white 6 green-white
3 white-green 7 white-brown
4 blue-white 8 brown-white
Extra care must be taken when at-
taching RJ-11 and RJ-45 connectors
to cable. Make sure you use the ap-
propriate crimping tool and verify that
the connector is properly seated into
the tool, or damage will result.
Contact Crown Technical Support for
additional information about working
with RJ-11 and RJ-45 connectors.
5.5 Load Supervision
Applications
The IQ-MC Load Supervision feature
can be used to monitor the amplifier
load in real time with almost any pro-
gram material. Average load imped-
ance is calculated as a function of
amplifier output voltage and current.
The system requires approximately
20-30 mA of average amplifier output
current for adequate supervision. This
allows typically low average output
power levels of less than ½ watt with
most loads. The maximum load im-
pedance for reliable system perfor-
mance is limited to about 50 ohms.
Higher impedances can be measured
but may require higher amplifier out-
put levels for reliable operation.
Most amplifier/load systems can be
configured and supervised by fol-
lowing these steps:
1 Configure your audio system us-
ing a known “good” load, then
enable the Load Supervision fea-
ture.
2 Provide typical program material
at a level high enough to light the
“test” indicator.
3 Run the system at this level until the
average impedance stabilizes. This
may take seconds to minutes de-
pending on level, duty-cycle, etc.
4 Set the nominal impedance at the
measured value average. This
optimizes the supervision algo-
rithm for voltage and current levels
versus the actual load. Note: A
higher nominal setting will require
higher output levels.
5 Set the high limit at twice average
and the low limit at one-fourth
nominal.*
6 Let the system run for extended
periods using any and all typical
program material.
7 Adjust the high/low limits, if neces-
sary, to account for any variance
in average measured impedance.
8 Enable error reporting, if desired.
* These limits are somewhat arbitrary but
should be a good starting point.