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900 Series V5.0: Installation Guide, April 1999
Two yellow LEDs - one per channel - are visible through the top cover of the enclosure.
When a channel is in an isolating condition, the associated LED is illuminated
continuously.
3.4.2.
Fire monitoring controllers
3.4.2.1. Zone monitoring unit - II955D
The Series 950 DIN-rail zone monitor powers and controls the operation of a zone of up
to 20 Series 860 Apollo fire detectors from a loop of Series 950 addressable monitors
and ancillary devices.
The zone monitor latches in the alarm state.
Use a 6.2 kW end-of-line resistor to monitor cables for open- and short-circuit faults.
Alternatively, you can use an active end-of-line monitor in conjunction with diode bases
and a capacitor of up to 50 µF fitted at the zone monitor wiring terminals.
The zone monitor is fitted with a bi-directional short-circuit isolator and is unaffected by
loop short-circuits on either loop input or output.
The Series 950 DIN-rail zone monitor is loop powered and operates at 14–28 VDC.
Figure 18: Wiring connections (Zone monitor unit – DIN mount)
Capacitor must be connected if active
end-of-line is used
Active
EOL
MCP
