Wavetronix VDR24 Radar - Manual (Page 64)

Support, Maintenance, Troubleshooting
64 VDR24 Radar Detection System, Rev 1.0
9.1.1. Real-Time Detection Activity (Visual)
A simple routine check of the radar detection system may be accomplished by watching
vehicles travel through the detection zone areas and noting the detection events as evidenced
on the VDR24 front panel indicators. Indicators are provided for each zone for each radar
sensor. Both radar sensors should record each vehicle detection, although the detection events
are not expected to be simultaneous, occurring at precisely the same instant in time.
9.1.2. VDR24 Indicator Status (Visual)
Other front panel indicators provide a view of operating status and their operating state should
be verified. Under normal operating modes, the Health indicator associated with each radar
sensor should be flashing green. The flashing activity verifies operation of each of the radar
sensor’s output processors. The green indication verifies that the radar sensors are in normal
operating mode and have not entered a failsafe state.
A failsafe state, the causal factors for which are set out in Section 7 of this document, is
characterized by a red Health indicator and all zones in a red, or forced detection, state.
As described in the foregoing sections, if the Island Relay (IR) circuit is de-energized and in an
active state, front panel detection indications will be influenced. An active IR state informs the
VDR24 that a train is occupying the crossing, a situation that suppresses normal detection
activity.
9.1.3. Communication Quality
Each radar sensor communicates with the VDR24 16 times per second. Each communication
event conveys presence and other radar operating parameters to the VDR24 Controller where
those states are then presented to connected railroad equipment. Each communication event
also includes checksum information that allows the VDR24 Controller to verify message
integrity. If there are missed communication messages because of radar failure, poor
communication cable connections, or severed cables, the VDR24 knows it within one second. If
the situation persists longer than 2 seconds, the affected radar channel immediately goes into
failsafe and the sensor’s health circuit is de-energized (opened). Likewise, if messages do not
pass the messages integrity tests, due to damaged cables or high levels of induced electrical
noise the system will revert to failsafe for the affected channel.
Message frequency and the quality of the message validation checks can be viewed in real time
for each radar channel by navigating to screen 2.3 (Communication Quality – Current) and
screen 3.3 (Communication Quality – History). See Section 7 of this document for details on
keyboard/screen navigation.
FFiigguurree 4444 -- VViieew wiinngg C Coom mm muunniiccaattiioonn Q Quuaalliittyy M Meettrriiccss