Keri Systems SB-293, Technical Reference

Page: 28 / 44

Technical Reference Manual – SB-293
01838-002 Rev. 3.0 Printing Date
Page 28 of 32 July-1998
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.
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.
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 Doors32 ™ 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.
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.
INPUT – an electronic sensor on the controller that detects a change of state in a device outside the
controller. See NORMALLY CLOSED, NORMALLY OPEN.
LOCK RELAY OUTPUT – a relay on the controller that changes its state upon command by the
controller. Typically the lock relay output unlocks a secure door.
NETWORK – a series of controllers linked together via a communication cable.
NORMALLY CLOSED – an input device that continually keeps a circuit active or complete. A state
change is generated when a normally closed device is opened. See INPUT.
NORMALLY OPEN – an input device that continually keeps a circuit open or incomplete. A state
change is generated when a normally open device is closed. See INPUT.
OUTPUT RELAY – a device that changes its state upon receiving a signal from the controller.
Typically the state change prompts an action outside of the controller such as activating or
inactivating a device.
GLOSSARY