The MHG 283 Optical Smoke Detector is a self-acting detector intended for the automatic fire alarm signalling as a smoke detector of the analog and addressable Electric Fire Detection and Alarm System LITES, especially for environs with explosion danger.

It responds to fouling – to both visible and invisible smoke particles (aerosols) on the principle of detection of scattered infrared radiation.

The detector may work:

• in zone 1 and 2 of a space with gas burst danger according to ČSN EN 60079-14
• in zone 22 of a combustible dust space according to ČSN EN 50281-1-2
• in space V1, V2, V3 with fire or explosion of explosives danger according to ČSN 33 2340

The MHG 283 detector is meant for cooperation with the analog Control and Indicating Equipments (C.I.E.) MHU 110 or MHU 111, MHU 115, MHU 116, MHU 117, eventually with the
addressable C.I.E. MHU 109. The detector contains a program that evaluates the fire situation pursuant to measuring of surrounding smoke concentration, namely in agreement with the
following adjustable characteristics:

• sensitivity of the detector; it monitors the surrounding smoke concentration increase compared to the quiescent state, that compensates the climatic and other influences (surrounding
  temperature, pressure etc.) continuously; the sensitivity can be adjusted in eight degrees that must be selected with reference to the detector`s combustion gas load that the detector responds to
• reaction time; the verification level of the fire situation is concerned; adjustable in four degrees, however they can’t be expressed through a simple time stamp, because the reaction time
  depends on the time progression of the fire situation
• dustiness look-out; it monitors the rest level of the detector, and upon this it evaluates the dustiness rate of the optical chamber and consequently the reliability of the detector; it can be adjusted in three degrees, or inactivated; it’s set in reference to the dust nuisance rate round the detector and to the setting of other parameters

Further in eight degrees the pre-alert sensitivity can be adjusted, it is always higher then the alert sensitivity (the pre-alert can be adjusted only by the C.I.E.`s MHU 110 and MHU 111). The
detector self regulates its internal working characteristics, if they don’t reply to the allowable tolerance, fault warnings occure.

The adjustable characteristics can be set either into the configuration program and recorded to the detector through the C.I.E. (MHU 110 or MHU 111), or they can be programmed right by
means of the preparation MHY 535 (MHU 109).

To a detection line the detector is to install through the use of the MHY 703 Mounting Base, eventually in environs without explosion danger through the MHY 713 Base.

The detectors comply with the standard specifications ČSN EN 54-7. For their use in the Electric Fire Detection and Alarm System they are liable to the compliance examination according to law No. 22/1997 Sb., in wording law No. 71/2000 Sb. and the relevant orders of the government. For the use in environs with explosion danger the detectors are liable to the homologation of the FTZÚ Ostrava - Radvanice A0 210.