The working voltage of the equipment is between 12 and 24 Volts without switching
(± 20%). The Transmitter Unit emits a beam of modulated infrared light at 1 KHz in
the form of a cone which crosses the space under surveillance to reach the
Receiver Unit. As the modulated infrared crosses the environment under
surveillance, it collects along its path all information that could suggest the start of a
fire. The events that intervene between Transmitter and Receiver affect the
infrared carrier, alternatively optically modulating it in frequency and in amplitude.
WORKING PRINCIPLE
The Receiver Unit demodulating from the infrared received the information that is
optically gathered, transforms each symptom of a possible fire into corresponding
electrical signals referable to “smoke”.
Such signals are electronically assessed by means of a special algorithm local to
the Receiver Unit, and are transmitted to the Beam Controller Unit. All the units
have a microcontroller that carries out a full scan of the working mode, i.e. not only
of the alarm, but also of faults, blinding and maintenance requests. The messages
are clearly given on the display and repeated by the four leds on the Unit, as well as
with the local led's on every individual piece of equipment. A message on the
display will indicate the type of event and the detector number.
NOTE: The Dip-Switch must always be used during installation to
determine the detector address number, also if is there only
one detector. In the loop configuration the Dip-Switch 4 must
stay in the «OFF» position.
The connection of one or more detectors is with leads of a minimum cross-section,
2
in accordance with current regulations, of 0.5 mm . For the type of cable to use
please refer to current regulations; it is not necessary to use shielded cable.
The detection of the start of a fire will mean information is sent from the field
(detector) to the Beam Controller Unit which will in turn send an alarm signal to a
central control unit. System resetting is possible both from the Beam Controller
with a dedicated command or from the central control unit or closing, by a normally
open contact, the two terminal blocks of the MRS module.
The Beam Controller Unit can be used to set the blinding fault relay switching delay
for every individual detector, for times from 0 to 90 seconds.
The Receiving Unit (RX) has an internal diaphragm that means it is possible,
following the instruction to mechanically set for the use of a diaphragm filter, to
solve environmental problems in particular architectural situation where there are
awkward reflections or the optical beam must work in limited spaces or get dirty
before the starting up.
ENGLISH
Mod. MII
rev. 01
SETRONIC Verona
53
