Elkron FAP54, Руководство по установке

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26 FAP54 Installation
4.4 OPERATION AND CHARACTERISTICS OF CONNECTION WITH CLASS B
The connection with open line or class B ensures a higher flexibility of installation compared to that with loop line.
However, the system can still signal malfunctioning due to the opening or short circuit of the detection line. As for the
loop line, the opening of a line section implies the lack of communication with the device/s, therefore the control panel
will signal it as field fault. In case of short circuit, the insulator upstream will isolate the line section downstream and
the control panel will give notice of the lack of communication with the isolated devices.
It is important to point out that on each line section max 32 devices are admitted.
Open line electric characteristics
•
Suggested cable: 2 x 1.5 mm² shielded.
•
Max open line total length: 2000 m
•
Cable total resistance: less than 100 Ω
NOTE: the max total length of the open line is the sum of the lengths of all the branches.
To find out the line cable resistance, short circuit the two wires at each branch terminal, and then use an ohmmeter to
measure the wires to be connected with the control panel terminals.
NOTE: if on the detection line there are short circuit insulators, they shall be removed before carrying out
measurement.
4.5 TEST PROCEDURE FOR DETECTION LINES
Before connecting the wires and the line cable shield with the line terminals of the control panel, check the following:
•
Electric resistance of the detection line which must be below 100 Ohm.
•
Electric insulation between the single detection line wires and the line cable shield.
•
Electric insulation between the line cable shield and the earth wire.
•
Connect the wires and the line cable shield with the control panel terminals and the earth connection point.
NOTE: the connection of the line cable shield with the earth point shall be carried out in the control panel and only with
a cable end.