Wavetronix VDR24 Radar User Manual
Page 36
Installing the VDR24 Controller
36
VDR24 Radar Detection System, Rev 1.0
5.4.2. Health Outputs
Two isolated, normally open contacts (one for each radar’s health signal) are provided. When
these contacts are closed radar health is known to be good, based on internal self-check
procedures that run continuously every sixteen seconds. When contacts open, health is deemed
to be unsatisfactory or unknown. Internally this causes the VDR24 to revert to a failsafe state,
with all detection outputs forced in to a failsafe, presumptive ‘presence’ state. These signals are
also intended to be utilized by other railroad equipment which is configured to respond to
potentially failed or uncertain status of the radar detection system. To utilize these health
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 Health+ and Health-
outputs and to Battery -.
VDR24 outputs for health status connect to railroad equipment in the same manner as zone
detection outputs, shown above. Like the Zone outputs, each Health output channel can control
up to 200mA of current.