Wavetronix VDR24 Radar - Manual (Page 22)

Introduction and Overview
22 VDR24 Radar Detection System, Rev 1.0
2.3.4.2. The VDR24 Controller Description
The VDR24 Controller is a multi-processor device that is designed expressly for demanding
railroad applications. Each radar sensor connects to an individual input and communicates
vehicle presence and radar health information sixteen times per second to its own dedicated
processor. Each radar processor instantly provides isolated Zone detection outputs to crossing
controller equipment, Exit gate Management Systems, or communication devices. An “open”
output signifies that a vehicle has been detected in a specific Zone and a “closed’ output
designates that the Zone is clear.
The VDR24 provides up to four separate Zone outputs and the device is typically configured in
such a manner that both radars are watching the same Zones, with their Zone outputs
combined together, but from opposite side of the crossing island.
2.3.4.3. Constant Monitoring, Failsafe Operation
Each radar sensor and its dedicated radar processor also analyze several continually running
processes that access radar and system health. Any missed communications from the radar
sensor, any failed internal health check process, or any loss of power instantly drives the
VDR24 into a failsafe state, opening all Zone outputs as well as the affected radar’s Health
output.
2.3.4.4. Vital Architecture – No Single Point of Failure
By utilizing separate processors for each radar sensor, the Island Radar detection solution
achieves a uniquely vital architecture with no single point of failure. This is in addition to the
100% redundancy afforded by utilizing two radar devices, both monitoring the same detection
zones from complimentarily positioned points on each side of the crossing island.
A third processor monitors and oversees the functions of the individual radar processors. This
system processor listens to communications emanating from the radar sensors and verifies that
each radar processor makes the proper decisions as the output states of the Zone outputs
reflect the presence/clear information communicated by the radar sensors.
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Display Port
Keyboard Navigation
Zone and Health Indicators
RS-232 Configuration Port
Power Terminal