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European Safety Systems Ltd.
Impress House, Mansell Road, Acton, London W3 7QH [email protected] Tel: +44 (0)208 743 8880
www.e-2-s.com Fax: +44 (0)208 740 4200
Document No. IS 2423-P Issue G 12-02-10 Sheet 4 of 4
(4)
connected to each terminal. If dc line monitoring is used cut
the link on the board (see figure 5 and section 14 of this
manual).
14)
End of Line DC Monitoring
On BExL25D and BExL15D loudspeakers, dc line monitoring
can be used if required. Both the 70V and 100V Line units and
the Low Impedance units have blocking capacitors fitted. It
should be noted that each loudspeaker has a 1M ohm bleed
resistor connected across the blocking capacitor and this
should be taken into account when selecting the value of the
end of line monitoring resistance.
The end of line monitoring resistor can be connected across
the terminals on the end of line unit. On the low impedance
units care must be taken with the polarity of the monitoring
voltage.
On 100V and 70V line units the end of line resistor used must
have a minimum resistance value of 4k7 ohms and a minimum
wattage of 2.5 watts
On low impedance units the end of line resistor used must
have a minimum resistance value of 2k ohms and a minimum
wattage of 0.5 watts or a minimum resistance value of 500
ohms and a minimum wattage of 2 watts. On the low
impedance units care must be taken with the polarity of the
monitoring voltage. If an end of line resistor is fitted to a unit
the links on the printed circuit boards of all loudspeakers in the
line must be cut for the dc blocking capacitors to be in circuit in
order to dc monitor the line (see figure 5).
