Wavetronix VDR24 Radar - Manual (Page 33)

Installing the VDR24 Controller
VDR24 Radar Detection System, Rev. 1.0 33
55.. IIN NSSTTA ALLLLIIN NG G TTH HEE VVD DR R2244 C CO ON NTTR RO OLLLLEER R
The VDR24 Controller provides power and communications to the radar sensors, as well as an
interface to a crossing controller or signal system processor. Installation and connection of the
Controller includes the following steps:
5.1. Physical Mounting of the Controller
The VDR24 Controller mounts to a wall or backplane surface using four keyhole flanges. Mount
the device at eye level, in a location where cables and connections can be conveniently routed
to each side. Connections made to terminals on the sides of the unit utilized pluggable terminal
strips connectors, so be sure to leave sufficient room to access the terminals and to secure
them (or release them) using the small set screws on the ends of each terminal.
Connecting Power to the Controller
The VDR24 operates from an 8-30VDC supply, typically provided by the battery supply
supporting the crossing (or interlocker single) site. Depending on the voltage level of the battery,
the VDR24 requires between 25 and 30 watts at 12VDC. The VDR24 then provides an isolated
24VDC power supply to the radar sensors. An Earth Ground connection is also required for
maximum surge and lightning suppression but this ground is completely isolated from the
railroad battery supply.
5.1.1. DC Power Connection
With the three-terminal Power terminal strip disconnected from the VDR24 Controller, Connect
DC power to the three terminal power supply input on the right side of the VDR24. Be sure to
heed proper polarity.
5.1.2. Earth Ground Connection
Connect the third terminal, labeled Earth Ground, to the main earth ground connection for the
equipment house or cabinet. This potential is isolated from the remainder of the system, but
necessary for maximum noise and surge protection.
5.2. Connecting the Radar Communication Cables to the Controller
Each radar sensor connects to the VDR24 Controller using a seven-conductor cable. In this
cable there is a pair of conductors that supply power to the radar sensors (red and black), two
independent RS-485 communication circuits, and a protective ground conductor.
Cable supplied by Island Radar is color-coded to match wire labels on each of the VDR24 radar
connection terminals located on the left side of the device.
Important: Go Step-by-Step
Make the initial power connections with the power terminal strip removed from its socket on
the VDR24 Controller. This Power terminal strip will be initially connected in Chapter 7.
Good Installation Practice
We recommend designating the radar sensor with the lowest numerical serial number as
Radar 1 in the installation and the sensor with the higher serial number as Radar 2.