May03-12: Freeze-Thaw Concrete Chamber Controller

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May03-12 Freeze-Thaw Concrete Chamber Controller

• Team Members
• Craig Rueter
• Steven Spencer
• Jason Stowe
• Eric Wulf
• Faculty Advisor
• Dr. James A. Davis

• Client
• Iowa Department of Transportation
• Date
• April 29, 2003

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Presentation Outline

• Introduction
• Project Activities
• Project Resources and Schedules
• Closing Materials

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Terms

• DOT
• Department of Transportation
• Programmable Logic Controller (PLC)
• A computer system designed to produce a desired
  set of outputs based on various inputs.
• Solenoid
• A device that uses an electromagnetic coil to
  operate another device, such as a valve or a
  relay.
• Thermocouple
• A device that measures differences in temperature
  by measuring the voltage produced by the
  thermoelectric effect.

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Introduction

• Acknowledgement
• Problem Statement
• Solution
• Operating Environment
• Intended Users and Uses
• Assumptions and Limitations
• End Product

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Acknowledgement

• The May03-12 team thanks Stephen Upchurch,
  Materials Laboratory Technician for the Iowa DOT,
  for his support and contributions to this
  project.

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Background

• Employees of the Iowa DOT use a machine to freeze
  and thaw concrete samples to simulate an Iowa
  winter to see how the concrete performs.
• These machines are known as freeze-thaw chambers.

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Problem Statement

• Due to the age of the freeze-thaw chamber
  controller in the materials lab, replacements
  were determined to be a top priority.
• The current control system is running on outdated
  hardware and is becoming increasingly hard to
  maintain.
• The current software and hardware limits the
  amount of control the user has with the actual
  chamber.

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Current Control Hardware

• The current control system consist of
• IBM PC XT
• Cyborg input/output system
• Relay Panel

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Current Control Software

• The current software was written in Basic 1.0 in
  the mid 1980s and has never been documented.

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Solution

• A new control system was created using a
  programmable logic controller that controls the
  chamber hardware and a Visual Basic application
  running on a modern Windows based computer for
  data logging and remote control of the
  programmable logic controller.

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Operating Environment

• The room that the freeze-thaw chambers are
  located in is not air-conditioned.
• The control cabling is being run though the
  ceiling and is subject to electrical interference
  from other cabling.

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Operating Environment

• The control room is located approximately 100
  feet away from the freeze-thaw chambers.
• The control room is a standard office environment.

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Intended Users and Uses

• The freeze-thaw chambers and the new control
  system will be used by employees of the Iowa DOT
  cement and concrete lab for the testing of
  concrete samples and for developing new testing
  techniques.

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Assumptions

• Initially only one freeze-thaw chamber will be
  controlled.
• No more than two freeze-thaw chambers will be
  controlled by the same system.
• The Iowa DOT will be able to order required
  equipment in a timely manner.
• The hardware that will be reused is in working
  order.
• The hardware that will be reused is already
  documented.

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Limitations

• Scheduling for time to use the freeze-thaw
  chambers.
• Scheduling conflicts between team members.
• Hardware ordering turnaround is dependent on the
  internal Iowa DOT ordering processes, supplier
  availability, and shipping delays.
• Constraints of industry standard concrete
  freeze-thaw testing techniques. Specifically the
  ASTM C 666 method B.

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End Product

• A new PLC that is properly programmed to run
  freeze-thaw cycles in the concrete chamber.
• A Visual Basic application that gives the users
  greater flexibility, more options, and
  communicates with the PLC through a serial
  connection.

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Project Activities

• Present Accomplishments
• Technical Approaches Considered
• Technical Approach Used
• Research
• Design
• Implementation
• Testing and Modification

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Present Accomplishments
TASK ACCOMPLISHED
Research 100
Revised PLC Code 95
Visual Basic Program 100
Testing 90
Documentation 95
Overall 95
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Technical Approaches Considered

• Upgrade the existing hardware and software.
• Existing hardware is antiquated.
• Commercial control system.
• Cost and lack of information.
• Custom system using a commercially available
  input/output card for a PC.
• Future upgrade problems.

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Technical Approach Used

• Duplicate the control system used in the
  aggregates lab.
• Existing code reuse.
• Well documented.
• Easy access to programming tools.

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Research

• Decide on the most appropriate hardware
• Learn ladder logic and assembly language that is
  to be used in the PLC
• Go through old, uncommented code to determine
  functionality that is still needed and what must
  be added
• Determine how a Visual Basic program can
  communicate with the PLC

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Design Overview

• The design of the project is broken into two
  parts.
• A PLC that controls the freeze-thaw chambers
  components and to handle error conditions.
• A PC application that communicates with the PLC
  in order to collect data and provide remote
  operation of the freeze-thaw chamber.

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PLC Design

• The PLC has internal registers for storing data
  from the various sensors attached to the
  freeze-thaw chamber.
• A programming language called ladder logic is
  used to program the PLC.
• Ladder logic is a visual programming language
  that is designed to mimic physical switches and
  relays.

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PLC Design
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PC Software Design

• Ability to programmatically read and write any
  register within PLC
• Design of database
• Functionality to graph temperatures of the tank
  and concrete samples
• Provide interface for users to retrieve data from
  prior samples and graph it

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Communication With PLC
PLC
Calling Program
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Can Read/Write All Registers
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Database Design
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Graphing of Current Sample
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Graphing of Historical Data
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Copy To Excel Feature
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Graphing of Historical Data
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Error Logging
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Design Constraints

• The product should be easily understood by the
  intended users in order to easily modify the
  design
• Microsoft Graphing Control is not very flexible
  and very poorly documented, but was chosen over
  3rd party controls due to budget constraints
• Microsoft Access was chosen as the data store
  despite its limitations also due to cost

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Testing and Modification

• Simulate the different scenarios of the chamber
  manually from a homemade switchbox
• Modify errors that occur from internal relays
  either being on or off in the PLC
• Go through an entire freeze-thaw process in the
  chambers
• Make sure errors are being detected and shown to
  the administrator from the control station

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Resources and Schedules

• Personal Effort Requirements
• Other Resource Requirements
• Financial Requirements
• Schedules

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Personnel Effort Budget
Task Estimated To Date
Meetings 80 hours 64 hours
Research 77 hours 73 hours
Design 67 hours 26 hours
Documentation 77 hours 63 hours
Testing 100 hours 50 hours
Development 105 hours 76 hours
Total 506 hours 352 hours
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Financial Budget
Item Estimated Cost Cost to Date
PC 1,500 0
Misc. Cmpts. 100 0
Control System 1,100 1,100
Poster Cost 50 50
Misc. Printing 15 10
Total 2,765 1,160
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Closing Materials

• Project Evaluation
• Commercialization
• Recommendations for Additional Work
• Lessons Learned
• Risk and Risk Management
• Summary

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Project Evaluation

• Project success.
• Project will be 100 complete by end of semester.
• Satisfaction of milestones.
• Completion of Visual Basic GUI - 100.
• Completion of PLC/GUI/hardware connections 85
  - serial comm.
• Completion of PLC/GUI interaction 100.
• Run of test system with new code/GUI 100.
• Implementation of design as new control 80.

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Commercialization

• The potential production cost
• The cost of a disk and copying software.
• The potential cost as commercial item
• 2600 PLC/PC/Software development time.
• The potential market
• Primarily DOTs, but possibly construction
  companies.

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Recommendations for Additional Work

• Another PLC can be used to run a different
  freeze-thaw chamber at the DOT with slight
  modifications to the PLC code.
• A second instance of the Visual Basic GUI could
  be used on the same PC to communicate with the
  other PLC using a second serial port.

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Lessons Learned

• The project went well overall.
• Satisfactory completion of milestones.
• Primary difficulty is insufficient time for
  serial communication conduit to be run.
• Tech knowledge gained.
• Understanding of PLC ladder logic.
• Better familiarity with Visual Basic coding.
• Things to do differently.
• Ask more questions early on instead of trying to
  solve issues with limited knowledge.

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Risks and Risk Management

• Anticipated
• Time to code is too long and gets into DOTs
  primary test season chosen design was completed
  within completion time
• Loss of member due to unforeseen difficulties
  situation was dealt with proactively and problem
  was avoided
• Poor choice of approach approach worked well
• Unanticipated
• Insufficient time to run conduit performed all
  other possible tests and will finish when conduit
  is done

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Closing Summary

• Need for project
• Previous code written in uncommented Basic
• Difficult to find replacement equipment
• No individual control of devices(valves, etc.)
• Chosen solution
• New control code in Visual Basic on modern PC
• Mitsubishi PLC used to replace old hardware
• Effectiveness of chosen solution Stephen
  Upchurch
• The system that was chosen is a vast
  improvement from what we had.
• The project team has done an excellent jobI
  believe they have exceeded our expectations.

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Questions?