Computerized Train Control System

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Computerized Train Control System

• by
• Shawn Lord
• Christian Thompson
• Advisor Dr. Schertz

2
Presentation Outline

• Project Overview
• Digital Train Control
• System Components
• Local Controller
• DCC Format
• DCC Encoder
• Switch Controller
• Sensor Controller
• Train Layout
• Design Implementation
• Results
• Future Work

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Project Overview

• Digital Train Control System
• Digital Control of Model Trains
• Control of Track Equipment
• Computer Interface
• Goals
• Fully control a digitally equipped locomotive
• Control of switches and layout features
• Sense train locations and layout state
• Link all control to a central computer
• Provide a train layout for future use
• Provide supporting documentation

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Digital Train Control

• How Digital Control Works
• Command Station
• Takes User Input
• Sends a command signal on rails of layout
• Decoder Card
• Resides in each locomotive
• Derives power and data from signal on rails
• Powers locomotives lights and motor

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Digital Train Control

• Standards
• National Model Railroad Association (NMRA)
• Sets Industry standards for model railroading
• Recently incorporated standards for digital
  control
• Digital Command Control (DCC)
• NMRA standard for digital train control
• Provides standards for communication with
  compatible Decoder Cards
• Advantages
• Locomotives are individually addressable
• One signal to all rails on layout
• Existing industry standards

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System Components
Block Diagram and Data Flow
Controller Application
Local Controller
DCC Encoder
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Local Controller

• Handles low level control of train layout
• Receives commands over serial link with PC
• Creates serial packet for control of locomotives
• Controls switches and accessories
• Polls track sensors for position reporting
• Implementation
• 8051 microprocessor
• Programmable Logic Device (FPGA)
• Signal buffering circuitry

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Local Controller

• Command List
• Local Controller Commands
• Reset All
• Locomotive Commands
• Send Override Packet
• Send Service Mode Packet
• Send From Command List
• Add to Command List
• Remove from Command List
• Clear Command List

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Local Controller

• Command List (contd.)
• Switch/Accessory Commands
• Set one output
• Clear one output
• Pulse one output
• Reset all outputs
• Sensor Commands
• Reset sensor timer
• Return one sensor
• Return all sensors

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Program Flow
Command from PC
Command Processing
Continuously write commands out to Encoder
Add command to queue
Locomotive
Write command out to controller
Accessory or Switch
Poll sensor(s)
Transmit sensor reading(s) to PC
Sensor
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Local Controller

• Memory Allocation (Memory Mapped IO)
• 0x00 0x07
• DCC Encoder
• 0x08 0x7F
• Output space
• 0x80 0x8F
• Sensor space

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DCC Format

• Transition based serial encoding
• Bit times
• 232us 0 bit
• 116us 1 bit
• Fully rectified signal provides power for trains

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DCC Format

• Basic Packet Format
• Preamble ten ones followed by a zero
• Address eight bits followed by a zero
• Data eight bits followed by a zero
• Error Check eight bits followed by a one
• preamble0address0data0error check1
• Speed Packet
• 01DCSSSS
• Other Packet Types

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DCC Encoder

• Receives data from Local Controller
• Transmits data in DCC format
• Connected to external bus of Local Controller
• Interrupts Local Controller upon completion
• Implemented in VHDL
• Registers
• 0x00 Command byte
• 0x00 0x07 DCC Packet to transmit

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DCC Encoder
Software Flow
transmit preamble
check command byte
command byte empty
command byte present
transmit idle packet
transmit data bytes
Interrupt processor on last bit
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System Components
Block Diagram and Data Flow
Controller Application
Local Controller
DCC Encoder
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Track Switches

• Allow locomotives to change paths
• Solenoid Controlled
• Double throw solenoid
• Requires 12v 5ms pulse
• Motor Controlled
• Small gear motor
• Requires 12v signal
• Motor stalls upon end of travel

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Switch / Accessory Controller

• Connected to external bus of Local Controller
• Latches data from Local Controller
• 16 outputs total
• 8 switches
• 16 accessories
• Sinks 600mA continuous or 3A pulsed
• Addresses
• Address 0 Latch A
• Address 1 Latch B

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Sensors

• Allow Location of locomotive on layout
• Layout divided into 21 blocks
• Current sensor on each block
• Current sensing
• 1ohm current sense resistor
• Differential voltage amplifier

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Sensor Controller

• Connected to A/D input of Local Controller
• Data Latched from External Bus
• 000C 0DDD
• C enables controller
• DDD selects 1 of 8 analog inputs
• 8 inputs
• Selected by analog switch
• Inputs filtered using an RC filter

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Train Layout
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Train Layout

• Designed for future use
• 2 separate loops
• 2 loopbacks
• 1 crossover
• 5 single ended sidings
• 4 track train yard
• 1 pass through siding

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Train Layout
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XS-40 Implementation of Design

• XS-40 FPGA Prototyping Board
• Manufactured by XESS Corporation
• Xilinx 4005E-pc84 FPGA chip
• 8031 uC
• 128byte SRAM
• Used to implement Design
• Local Controller uses 8031
• DCC Encoder implemented on FPGA
• Interface Board Designed
• A to D converter
• 256byte EEprom Memory
• External Bus

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Results

• Hardware
• Train Layout Built and Wired
• Two DCC Compatible Locomotives
• Local Controller Designed and Implemented
• Sensors Designed and Tested
• Switches Designed and Tested
• Controller Boards
• (Main, Switch, Sensor)
• Design and Layout complete
• Not manufactured

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Results

• Software
• Serial interface designed and Implemented
• Train control designed and implemented
• Switch control designed
• No software support for sensors
• No support for service mode packets

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Future Work

• Manufacture and Build Controller Boards
• Software
• Sensor polling
• Service mode packets
• Decoupling and Crash prevention

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Questions ?
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Web-based Control InterfaceFor a model train
control system
By Kevin Sendra Advisors Dr. Schertz Dr.
Malinowski
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Presentation Outline

• Overview of the Project
• Project Description
• Results
• Problems
• Future work

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Project Overview

• Add-on to the Local Control System
• Allows control and/or view of the layout from the
  internet

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Project Description

• Block Diagram

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Client Description

• Allows the user to control the speed and
  direction of multiple trains
• Displays connection information and command
  status (from server)
• Image Map for switch control (no switch control
  currently)

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Client Flowchart
Start
Thread Delay
Thread Receive
Get Parameters
Create GUI Elements
Send Command To Server
Receive From Server
Connect to Server
Append to Text Area
Wait .5s
Start Threads
Event Handling
Close socket End threads
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Current GUI
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Local Computer

• Server
• Waits for a connection
• Logs connections
• Receives commands and sends them to the serial
  port
• Acknowledges commands
• Sets session length to 10 minutes
• Webcam Software
• Dorgem

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Server Flowchart
Server Start
Thread Timeout
Start Thread
Compare Stored Time To Current Time
Wait For A Connection
Log Connection Store Time 10m
Disconnect If Equal
Wait For A Command
Acknowledge
Close Connection
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Webcam Viewer
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Results

• Working graphical user interface
• Allows locomotive speed and direction controls
• Displays command status
• Working Server
• Viewable webcam stream

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Problems

• The computer
• Speed
• Security and Software
• Java versions and Internet Explorer or Netscape

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Future Work to be Completed

• Implement switch control
• Allow a configuration file to set up certain
  elements of the interface

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Train Control
Train Control Train Control 800x600
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Questions
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Local Computer Interface
For A Digital Train Controller
By Zachary Kirkpatrick Advisor Dr. Schertz
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Presentation Overview

• Introduction
• Block Diagram
• Functional Description
• Design
• Accomplishments
• Complications
• Conclusion

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Introduction

• Digital Train Controller
• Local Computer Interface
• User Input Instruction
• Send Out Instruction
• Train Moves

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Block Diagram
Altered Input
Local
User Input
Computer
Instruction
Instruction
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Functional Description

• Input User Instructions
• Decipher User Instructions
• Alter Code Of Instructions
• Send Out Instructions To Microprocessor

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Design Flow Chart
User Input
Power
Switch
Speed
Movement
On
Off
Up
Down
Forward
Reverse
Track
Train
Go Back To User Input
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Design

• Write Software To Draw Control Buttons
• Output The Appropriate Information For The
  Corresponding Button Pressed
• Use MFC Library of C

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Design Control Buttons

• User Buttons
• Power On
• Power Off
• Switch Tracks
• Speed Up
• Speed Down
• Move Forward
• Move In Reverse

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Accomplishments

• Buttons Were Created
• Buttons Are Active
• Buttons Are Either
• Functional
• Personal Constructors

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Accomplishments
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Accomplishments
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Accomplishments
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Accomplishments
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Accomplishments
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Accomplishments
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Accomplishments
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Accomplishments
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Complications

• Sickness The First Several Weeks
• Slider Buttons
• Auto-creation Of Files In MFC

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Auto-creation Example
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Conclusion

• Buttons Are Created
• Basis For Button Implementation Created
• Need To Finish Button Implementation

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Questions