GNA42 base

On the printed circuit board of MAR42 module there are terminals by means of which the base is connected to the fire watch line. One pair of terminals marked with + and – is used for connecting line A, while the other pair is used for connecting line B. By means of the terminal marked with E the shields of the two wires are connected together. The base cage has a mechanical lock preventing from taking the detector out of the base. In order to get rid of this lock, a special latch has to be broken off (see in the picture.) In case the lock is not broken off, the mounted smoke detector can be taken out of the base only by means of a special key.

GNA42 base equipped with MAR42 module feeds and controls the optical detector mounted in the base. In MAR42 electronic module optical detectors can be in three states:
1. No detector or its improper current consumption while the detector is in the operational state.
2. Working in the operational state.
3. Alarm state.
MAR42 module has a unique address encoded in a given AFS42 system – from 1 to 99. AFS42 central set “asks” each base connected to AFS42 three times a second and receives information on the three states of the detector. On the basis of the information concerning the states, AFS42 makes decisions resulting from the system configuration.
GNA42 base has a short circuit insulator on the printed circuit of MAR42. AFS42 central set is not informed about the insulator's state while the base is “being asked”. However, AFS42 can spot the bases with open insulators on the basis of the one-side answers given by the bases in the loop line. The detector, placed in the base in which the insulator is open, is fed and “observed” by the central set from the side with no short circuit.

Type of the linear element addressable with a built-in short circuit insulator
Power supply voltage 20V (od 12V do 30V)
Current consumption 200uA
Works with fire alarm central set AFS42
Insulator's principle of operation two-way automatic voltage-sensitive
Cut-off voltage 7V
Wtrącona szeregowa resistance 0,08Ohm
Type of the transmission to the central set digital

Protection against reverse power supply polarization yes
reaction time of short circuit in the line 10us

Base dimentions (diameter x height) 102 x 21 mm

Base cage material white ABS

Degree of protection IP54
Work temperature range from -25 to +50 degrees C

Storage temperature range from -25 to +50 degrees C

Relative humidity 80%

1. 1. GNA42 base for AFS42 system - data sheet
   42-gna42-kk-090730-en.pdf