1. By Anthony Moody Rhys Porter Nicolas Wilson

2.  Background  Objectives  Design  Normal Operation  Logic  Failure  Issues and solutions  Improvements

3. Level Crossing:  Flags as indicators  Patent of Level Crossing  Electronic Bells  Cross-Buck “X” sign

4.  12 Digital Inputs  4 Inputs able to run as analog  6 Relay Outputs  LCD Display  Operating Buttons Functions:

5.  Design and Implement a Level crossing using analogues available in the lab and Moeller  Fail safely and appropriately handle exceptional cases

6.  Fail Safe  Moeller Easy “PLC”  Power Supply  Strobe Light as bells

7.  Proximity Based Train Detection  Safety Conscious Design  Verbose Fault/Warning Memory for Diagnosis and Reporting  Some Automatic Fault Recovery  Intersection Obstruction Detection  10 effective outputs from 6 SSRs  Emergency Stop  Fail Safe on Controller Power Loss

9.  Wait for train  Trigger warning lights  Lower boom gates  Set train lights accordingly throughout  As train leaves do in reverse order

12. Simplified Underlying Logic

13.  Loss of power to controller  Sensor failure (boom gates)  Emergency switch  Obstructed intersection  Train detection failure  Erroneous train signals to boom gate

14.  Issue: Limited outputs  Solution: Use external transistor with diode or gate  Issue: Potentiometer too sensitive  Solution: Use rheostat in series with resistor

15.  Moeller Expansion Module if required  Active monitoring to larger control system