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AXYS
IndustryAmp-DN User Manual Rev 3.0
®
The Input Mode setting in WinControl (at Input
Common
parameters) allow selection of auto-
switching mode. A brief description of each mode follows;
see the WinControl Help files for full details.
Normal
Auto-switching is disabled. All inputs are active, if more
than one inputs is selected to go to an output (selected
using the matrix) then the inputs are summed.
Level-controlled priority switching
When enabled, the inputs will switch when the signal
level at the detection point drops below -60 dBFS (default
value), but this threshold may be set to any level between
-80 dBFS and -20 dBFS. The detection point is either 'At
input' or 'After processing'. In the latter case filtering may
be applied, for example to reduce the level of an input
pilot tone. When using analogue inputs, the relationship
between dBFS and dBV's measured at the amplifier's
inputs should be taken into consideration; WinControl's
Help files give full details.
It is also possible to set a Hold Time, so that unwanted
switching does not occur between natural gaps in the
programme.
Pilot tone-controlled priority switching
It is common practice in critical audio systems to permanently
route a low level, high-frequency tone through the system.
The presence of this pilot tone can then be detected by various
items of equipment to verify the continued operation of the
audio paths. Set Input Mode to Pilot tone-controlled priority
switching to enable this mode.
The IndustryAmp's pilot tone detector on the analogue
inputs operates in the frequency range of approximately
20 kHz to 28 kHz. The detector is most sensitive in the
center of this frequency range, the detection threshold is
not software configurable. On the digital (Dante
the frequency range is 19.2 kHz to 23.5 kHz and the
threshold may be set between -10 dBFS and -60 dBFS.
The amplifier's action on non-detection of a pilot tone can
be configured via WinControl. A fault condition can be
"flagged", and/or the input can be set auto-switch to that
with the next priority.
201911/IAMPDN_3.0
>
A notch filter should be inserted to suppress the
pilot tone if its frequency is less than half the
internal processor's sample frequency (F
24 kHz). If the pilot tone is not sufficiently suppressed,
signal detection (and other functions such as frost
protection and Autogain) will not function properly.
Further, this may result in excessive dissipation in the
power amplifiers and/or connected loudspeakers, or
interference with the internally-generated tone used for load
monitoring. Pilot tone frequencies above F
suppressed by the anti-aliasing filter of the ADC. Any pilot tone
frequency received via the digital inputs is < Fs/2 by default.
Take notice of the following when configuring the parameters for
the input pilot tone detection:
It is advised to use a few seconds of Grace time in order
to avoid spurious input pilot tone monitoring errors.
Use a fixed frequency if the frequency of the externally
applied pilot tone is known and fixed.
See WinControl help file for details.
Failure relay
The single-pole changeover failure relay may be wired to a
'common fault' or other external fault monitoring system
so that any fault condition detected by the IndustryAmp
is immediately reported. The conditions which cause
activation of the failure relay may be defined in WinControl,
and may include any or all of: DSP/amplifier/Dante
faults, load monitoring, internal temperature sensing, fan
operation, pilot tone detection, etc. See the WinControl
Help files for full details.
If it is required to interface the IndustryAmp to impedance-
sensing fault-monitoring equipment such as the AXYS
Cerberus, the failure relay contacts may be re-configured
) inputs
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by moving an internal jumper. See "fig.5: Failure relay" on
page 14 for connection details.
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17
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