Wavetronix VDR24 Radar - Manual (Page 16)

Introduction and Overview
16 VDR24 Radar Detection System, Rev 1.0
a location where the radar based detection system may be
used to detect trains on track circuit dead sections.
Delay Time For the purposes of the Island Radar detection system, delay
is the time period during which a continuous detection state on
an established zone must be present before the VDR24
Controller passes that condition to an Output Channel for
signaling to railroad equipment.
Device USB Port A Type B connector effecting a USB interface where a
connected Host USB port supplies power and manages the
communications, e.g. a device that is controlled by a laptop
computer USB Port.
Dry Inputs and Outputs Unpowered contacts or switches. In order for Dry Contacts to
provide control (e.g. a relay) a power source must be
externally provided.
Extend time For the purposes of the Island Radar detection system, extend
is the additional time period that a Channel Output remains in
an active detection state following a valid detection event. It is
intended to assure that a minimum pulse width signal is made
available to connected Railroad Equipment.
Firmware Microprocessor executable code that defines the operations
and operating parameters of a device.
Host USB Port A Type A connector effecting a USB interface that [provides
power and manages communications to a USB Device Port,
e.g. a laptop computer that is connected to a device being
controlled by an application residing on the computer.
IR Circuit Abbreviation for Island Relay Circuit, generally a series
combination of vital relays that signals when a train is
occupying any section of track over a Crossing Island.
Railroad failsafe convention specifies that the series contacts
are closed when no train is present and that the series
contacts open when a train is present.
ITS Intelligent Transportation System, the general category of
systems that provide highway and rail traffic operational data,
including radar based sensing devices.
Lanes For the purposes of the Island Radar detection system, Lanes
are the pathways where vehicles are intended to be detected.
When the system is used for train detection at Crossovers,
Lanes are synonymous with tracks. See Channels and Zones.
MTCD Minimum Track Clearance Distance is the entire Crossing
Island Area, the formal railroad industry name for the Crossing
Island area
Open Contacts For the purposes of the Island Radar detection system, an
open contact is an isolated, solid state, electrical switch that
does not establish a connection and therefore does not
conduct current.