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1. GENERAL INTRODUCTION
1.1
Introduction to the SM40 Surveillance Centre
In large public address distribution systems, which often play a key role in alarm and evacuation
installations, it is vital that the correct functioning of the large number of amplifiers and loudspeakers used
can be verified.
The SM40 Surveillance Centre is designed to monitor the status of amplifiers, loudspeakers, and cabling in
large PA systems. Because it pinpoints any failures in the system, it saves a great deal of time, minimising
repair costs as well as ensuring that the system is fully functional at the earliest possible moment.
On detection of a malfunction, error messages are generated automatically, giving the precise time and
location of the fault. These messages can either be relayed to the system's LCD display, or sent to an external
printer for a permanent hard-copy record of the malfunctions. The messages can also be linked to warning
lamps, buzzers, or personal paging units, alerting security and maintenance personnel.
The possibility also exists to automatically switch in a spare amplifier in place of an amplifier which becomes
faulty.
A pilot tone signal is generated which is inserted into the Test inputs of Philips SQ45 power amplifier range.
The Surveillance Centre is able to scan for the presence of this signal in up to 4096 monitoring devices,
located in strategic places (at amplifier outputs, loudspeaker cabling junction boxes, inside loudspeaker
enclosures) throughout a PA distribution system. It can also receive 'internal error' information from an
SM40 Routing System itself, as well as responding to external sensing devices such as smoke detectors and
micro switches.
Being controlled by a microprocessor, the system is particularly flexible, specific functions being easily
programmed and changed to allow for alterations in the PA system configuration and surveillance
requirements.
Because the system is built around 19-inch rack mounted Euro Card circuit boards, expansion or alterations
to the system are quickly and easily carried out.
A total Surveillance Centre would comprise:
- 19-inch rack unit, containing a microprocessor controlled SM40 Surveillance Centre
- 100V loudspeaker line, and low voltage loudspeaker, monitoring devices; external warning devices
(lamps, buzzers, etc.)
- printer, or computer/printer combination.
All SM40 Surveillance Centre internal wiring is particularly installer friendly due to the 'Quick Fit'
connectors used.
Standard twisted two core screened microphone cable is used to carry data and 15V power between the
system and the interlinked Amplifier/Loudspeaker Surveillance Boards.
All SM40 Surveillance Centres are built around the LBB 1370 Basic (starter) System, which is able to
sequentially scan 8 Test Lines, each containing up to 128 monitoring devices; receive error input from
2 external sources, activates several relay error sets and synchronises the real-time clock.
The single 19-inch rack frame, capable of holding 9 circuit cards, has enough room to accomodate the Basic
System plus 5 extra cards. Adding these cards expands the system, enabling it to feed more amplifiers with
the Pilot Test Tone; scan a greater quantity of Test Lines and/or receives a larger amount of error inputs
from external devices. However the system is limited by the number of Termination Boards installed.
When a system's requirements exceed the space offered in a single rack frame, or extra termination boards
are required the SM40 Extension Frame LBB 1360 is available. These frames can be linked together to
expand the system.
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