Project 1 – Level Crossing

By Anthony MoodyRhys Porter

Nicolas Wilson

Background Objectives Design Normal Operation Logic Failure Issues and solutions Improvements

Overview

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

Background

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

Moeller 719-DC-RC

Functions:

Design and Implement a Level crossing using analogues available in the lab and Moeller

Fail safely and appropriately handle exceptional cases

Objectives

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

Design

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

Key Features

Output Wiring Diagram

Normal Operation Wait for train Trigger warning lights Lower boom gates Set train lights accordingly throughout As train leaves do in reverse order

Logic

Zone Based pseudoLogic

Simplified Underlying Logic

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

Failure & Exceptional Cases

Issue & Solutions Issue:

Limited outputs Solution:

Use external transistor with diode or gate

Issue: Potentiometer too sensitive

Solution: Use rheostat in series with resistor

Moeller Expansion Module if required Active monitoring to larger control system

Possible Improvements

HHSF & Questions