Vital solid state controller

摘要

A vital programmable logic device (VPD) is provided having at least two microprocessors. The VPD is configured to provide failsafe operation of a vital control system while operating in a closed circuit environment. In at least one embodiment of the present invention, railroad grade crossing signals are controlled by the VPD.

主权项

1. A railroad signal processing device comprising:
a processing device output configured to provide complementary control of one or more railroad signaling devices; a first controller configured to generate a first input-dependent output signal by performing a logic process using an input signal set comprising one or more railroad input signals representing one or more conditions on a railroad track; a second controller configured to generate a second input-dependent output signal by performing the logic process using the input signal set, wherein the first and second controllers do not share components affording alternative energy or logic paths and provide independent and redundant processing of the input signal set; wherein a failure signal configured to set a railroad signaling device to a safest condition is provided at the processing device output if at least one of the following occurs:
failure of one or more components of the railroad signal processing device;integrity testing failure by the first controller;integrity testing failure by the second controller; further wherein, when the first and second controllers both pass integrity testing, and when there is no component failure within the railroad signal processing device, the input-dependent first and second output signals are identical and are used to generate complementary first and second control signals configured to control a railroad signaling device coupled to the processing device output.