Scantronic 808, Инструкция по установке и программированию

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3. Installation
Wiring FSL zones
Each FSL zone uses a two wire closed loop, with two resistors of different
values to differentiate between a ‘Circuit’ and ‘Tamper’ signals. A 2K2
(2.2Ký) resistor is fitted in series at the end of the wired loop (EOL-End-Of-
Line) and a 4K7 (4.7Ký) resistor fitted across the alarm contact. All tamper
devices are connected in ‘Series’ with the return feed to the end station, see
Figure 9.
2k2 EOL
4k7
Zone 1
CCT
Alarm contacts
Tamper Loop
Zone 1
AT
Note: When wiring FSL zones, link out the
anti-tamper terminals of each zone in use
on the main connnector and expander
cards.
Figure 9. Wiring Diagram for Single Alarm Contacts and Tamper Wiring.
With the loop in a normal state and the alarm contacts closed (shorting out
the 4K7 resistor), the total resistance of the loop is 2K2 ohms. When the
alarm loop is opened and the short removed from the 4K7 resistor, the
resistor is brought into the circuit and the resistance of the loop is increased
to 6K9 causing the end station to detect an alarm condition. If a tamper
device is opened, the loop resistance will be open circuit and the end station
will detect a tamper signal.
The wiring resistance should be restricted to a maximum of 100 ohms. The
recommended maximum cable distance per zone is 200 - 300 metres.
Figure 10 shows an alternative method for connecting several contacts in
one loop.
Note: This example is not recommended, as the individual alarm
contacts are not completely fully supervised.
808 sect 3 installation.p65 9/8/98, 10:27 AM 19