Patent ID: 6463337
Filing Date: 2002-10-08
Classification: B61L

Abstract:
A method of controlling rail train movement through a railroad network including signals and switches in which the condition of a signal and the position of a switch is determined by vital output signals which are provided by a railroad signal output module, which module has a master microcontroller and a plurality of slave microcontrollers connected thereto, the master microcontroller including a pseudo-random number generator providing numbers in a predetermined sequence and a periodic clock signal, with the generator periodically changing the pseudo-random number in accordance with the time period of the clock signal, and wherein each slave microcontroller includes a pseudo-random number generator providing numbers in a predetermined sequence, which sequence is the same as that of the master microcontroller, the method including:sending periodic clock signals from the master microcontroller to one of the slave microcontrollers; sending a pseudo-random number from the master microcontroller to the one slave microcontroller at a time closely related to that of the clock signal; comparing the pseudo-random number from the master microcontroller to the pseudo-random number from the one slave microcontroller, if said clock signal is received at the one slave microcontroller within a window period of time determined by the one slave microcontroller; and generating an output signal for use in controlling train movement at the one slave microcontroller if the pseudo-random numbers from the master microcontroller and the one slave microcontroller are identical.