Keri Systems SB-293 - Manual (Page 101)

Keri Systems, Inc. Technical Reference Manual – PXL-250 and SB-293
Revision 5.5 P/N: 01836-004 Page 101
13.0 Glossary
ALARM RELAY OUTPUT – a relay on the controller that changes its state upon
command by the controller. Typically the alarm relay output activates an audible alarm
used for door alarms.
AUXILIARY RTE – a second input source that informs the controller that someone
has requested egress from a secure area. RTE and REX are common abbreviations.
See REQUEST TO EXIT.
COM PORT – A COM port is a hardware device that allows a computer to
communicate with external devices.
CONTROLLER – a central unit containing a microprocessor, a database, inputs, and
outputs. The microprocessor processes information received from the inputs,
compares it to information in the database, and determines if an output should be
generated.
DOOR FORCED ALARM – a door that is forced open generates a door forced
alarm.
DOOR HELD OPEN ALARM – a door that is held open beyond the Open Time (as
programmed in the Doors program) generates a held open alarm.
DOOR SWITCH – a switch that reflects the current state of the door: if the door is
open, the switch is open; if the door is closed, the switch is closed.
EARTH GROUND – an electrical connection point that brings all electrically neutral
lines to the earth's surface potential (essentially zero potential). A good earth ground
protects electrical devices from transients such as power surges and lightning strikes,
and drains electrical interference from data, communication, and power lines that
support these electrical devices. The ground wire is green with yellow tracer.
ELECTROMAGNETIC INTERFERENCE – Excess electromagnetic energy
radiated by an electrical device that may affect the operation of other electrical
devices.
EMI – see ELECTROMAGNETIC INTERFERENCE.
FAIL-SAFE – fail-safe means that if the power should fail at a door, the door will
automatically unlock allowing egress. A fail-safe door ensures people will be able to
exit a secured area through that door in the case of an emergency.
FAIL-SECURE – fail-secure means that if the power should fail at a door, the door
will automatically lock and not allow entrance, but will continue to allow egress. A
fail-secure door ensures a secured area remains secure regardless of the situation.