Wavetronix VDR24 Radar - Manual (Page 35)

Installing the VDR24 Controller
VDR24 Radar Detection System, Rev. 1.0 35
5.3.2. Island Relay Connections
In a crossing application, when trains are occupying the crossing, the VDR24 and associated
radars are responding to numerous detection events (due to the train’s chaotic radar cross
section reflections). During this time it is recommended that the radar detection subsystem
ignore detection events. It does so by utilizing the Island Relay or IR circuit. To connect IR to the
VDR24, Battery+ should connect to separate contacts of the railroad’s IR relays, in series with
all track circuits. This combined signal is then connected to IR+ and from IR- to Battery ground.
ground. The connection for the IR signals is the same as the connection for the XR signal
shown above.
5.4. Connecting Controller Outputs to Other Equipment
The VDR provides simple interface to any type of crossing controller, vital processor, or relay
circuit. Individual zone detection outputs are provided along with a health check signal for each
radar sensor.
5.4.1. Zone Detection Outputs
Four isolated, normally open contacts (one for each detection zone) are provided. When these
contacts are closed no vehicle or train presence is detected. When contacts open, a vehicle or
train within the corresponding zone has been detected. To utilize these zone detection outputs,
connect system Battery+ and a solid state or mechanical relay contact from the equipment
being controlled, in a high side or low side configuration, to the Zone+ and Zone - outputs and to
Battery -. Each output channel can control up to 200mA of current.
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+
_
Zone and Health Detection Relays
Normally Open
VDR24 + and – outputs for
Zone and Health signals
+12V Battery Supply
B12
Battery Supply Ground
N12
Relay isolated Zone and Health signal
inputs to railroad equipment