Glossary
Alarm condition
– A fire or overheat around the Digital LHD cable which activates the cable and triggers the
AlarmLine II Digital EN Controller.
Cable glands
– Used to form a dust-proof and weatherproof seal around a cable entering the AlarmLine II
Digital EN Controller.
Digital linear heat detection cable
– a sensing cable comprised of a pair of twisted low resistance
conductors that fuse together at a specific temperature and induce an alarm on a fire panel or
interface module.
End of line resistor
– A component which allows a residual current flow through a circuit to monitor the
integrity of the circuit. In the event of a break in the circuit, current will stop flowing completely and a
trouble or fault signal will be triggered.
Fault condition
– A break in one or both cores of the Digital LHD cable or a malfunction of the AlarmLine II
Digital EN Controller.
Independent mode
– The mode on the AlarmLine II Digital EN Controller where both zones operate
separately. Each zone can trigger a fault or alarm, or be in the normal state, regardless of the state of the
other zone.
Interlock mode
– The mode on the AlarmLine II Digital EN Controller where the alarm relay outputs will only
activate when both Digital LHD cables go into alarm. If one cable triggers but not the other, the alarm
relay outputs will not be triggered.
Junction box
– A secure, dust-proof and weatherproof enclosure to protect a join between two lengths of
Digital LHD cable or a length of Digital LHD cable and leader cable.
Leader cable
– A non-temperature sensing cable which transmits the signals between two components in
the system, e.g. the AlarmLine II Digital EN Controller and the Digital LHD cable. Does not provide fire
detection and may be fire-rated to continue functioning even in a fire condition.
Two-wire RS-485 Modbus RTU/ASCII Communications
– An industry standard, signalling protocol used to
communicate information between components in a system, for example a SCADA system or PLC. Often
used to provide more information to be communicated than simple open or closed status communicated
by a relay output.
Zone
– a single circuit of AlarmLine II linear heat detection cable connected across either a AlarmLine II
Digital EN Controller or a fire panel and an end of line resistor.
