Specifications

149 Beaconsfield Street,
Silverwater. NSW 2128
Phone: [phone]
Fax: [phone]
RMA750 Overview
Following is an overview of the RMa750 6 channel amplifier including installation and
programming aspects when using:
1) CRESTRON CNPI/ CPI-16B Custom Panel Interface card.
2) AMX AXP-CPI16 Custom Panel Interface card.
These cards are able to accept up to 16 inputs from the amplifier and the cards also have 16 outputs
which can be used to control a number of aspects of the amplifier.
In addition to the standard amplifier (KMa750), we add a control system to amplifier interface. This
interface takes various analogue and status signals within the amplifier and converts them to a logic
level (which is buffered) which can then be interpreted by the custom interface cards for processing
by the control system.
It is important to note that the use of the Crestron/AMX system in relation to the amplifiers is a
supervisory one. On this basis, the normal operation of the amplifier is not dependant on the control
system at all. The control system merely monitors various operational aspects of the amplifier and
reports any faults to the system where appropriate action can be taken, either by an operator, a
program or internally within the amplifier (which can be fed back to the control system).
Ultimately it is felt the system should operate as a fault monitoring system which can/ should/ will
isolate offending channels, report to the system and allow for redundancy aspects if required.
Due to the 6 channels of the RMa and the limit of 16 channels of the Panel Interface cards, an
overall fault detection circuit for each channel has been employed and is referred to as the input to
output (in/out) fault detect circuit.
The input to output fault detection circuit is very broad in its detection ability and has to be a two
way type of detector. Simplified, the fault may be input signal but no output or, output with no
input signal. Any difference between input or output has to be considered as a fault and reported to
the system.
The detection circuitry is basically a differential type circuit which null’s input voltage against
output voltage. The output of the amplifier is applied to the differentiating circuit without any
compensation. The input signal is applied to the circuit with compensation to emulate the
bandwidth and phase response the amplifier. The circuit is full amplifier bandwidth.
Any deviation/difference of signal, other than the fixed input to output gain of the amplifier and a
small window of tolerance within the detection circuitry, will output a signal to a micro on the
amplifier interface for analysis. The in/out detector will show any fault including, D.C supply faults
(post pre-amp when signal is applied), D.C. on the output, oscillation, abnormally high noise (that is
not input born), a muted amplifier, various circuit failures, bad connections, sustained clipping etc.
The circuit does not need signal to alert the system if the amplifier is outputting a signal with no
input signal applied such as D.C., oscillation or out of specification noise. This then also doubles up