Bonitron Air Demand Bonitron Air Demand SchedulerScheduler

Design ReviewDesign ReviewVanderbilt Senior DesignVanderbilt Senior Design

Alex BrownAlex BrownAjmer DwivediAjmer Dwivedi

Cory HaughCory Haugh

February 04, 2008February 04, 2008

IntroductionIntroduction

Air Demand Air Demand SchedulerScheduler Reduces peak Reduces peak

power consumptionpower consumption Selects 1 of 2 Selects 1 of 2

HVAC units to run HVAC units to run at a timeat a time

Allows for manual Allows for manual control using user control using user overridesoverrides

ObjectivesObjectives

Production ready prototypeProduction ready prototype Low cost microprocessorLow cost microprocessor RS-232 I/O functionalityRS-232 I/O functionality Identical logic Identical logic All other specifications are to remain All other specifications are to remain

the samethe same Preserve existing packagePreserve existing package

RequirementsRequirements Input PowerInput Power

115VAC, 50/60Hz115VAC, 50/60Hz Control Signals 24 VACControl Signals 24 VAC

InputsInputs Thermostat 1: Air Conditioning 1, Heat 1Thermostat 1: Air Conditioning 1, Heat 1 Thermostat 2: Air Conditioning 2, Heat 2Thermostat 2: Air Conditioning 2, Heat 2

OutputsOutputs Unit 1: Air Conditioning 1, Heat 1Unit 1: Air Conditioning 1, Heat 1 Unit 2: Air Conditioning 2, Heat 2Unit 2: Air Conditioning 2, Heat 2

EnclosureEnclosure NEMA-12 Wall Mountable w/Quick Release Door Latch (10’’ x NEMA-12 Wall Mountable w/Quick Release Door Latch (10’’ x

6’’ x 4’’)6’’ x 4’’) Operating TemperatureOperating Temperature

0 to +40 Degrees Celsius0 to +40 Degrees Celsius Storage TemperatureStorage Temperature

+20 to +65 Degrees Celsius+20 to +65 Degrees Celsius HumidityHumidity

Below 90%Below 90% AtmosphereAtmosphere

Free of Corrosive Gas and DustFree of Corrosive Gas and Dust

ApproachApproach

Extract existing design from Extract existing design from previous group’s documentation and previous group’s documentation and new hardwarenew hardware

Replace FPGA development kit with Replace FPGA development kit with microcontroller microcontroller

Develop PCB design partitioning Develop PCB design partitioning circuit componentscircuit components

Fabricate assemble and test designFabricate assemble and test design

System DiagramSystem Diagram

Main Board

Power Conversion

Signal Conversion

120V AC Power Supply

Thermostat 1

Thermostat 2

Heat

A/C

Controller

Output Relays

Heat

A/C

HVAC 1

HVAC 2

RS232 Conversion

Computer

5V

ON/OFF

ON/OFF

Demand 1

Demand 1

Gnd

PicKit 2 Programmer

Vp

p

PG

D

PG

C

ProgrammingHeader

Vp

p

PG

D

PG

C

RxD

TxD

Vcc Heat

RxD

TxD

RxD

TxD

Gnd

Vpp PGD PGC

RA0RA1RA2RA3RA4

RA0RA1RA2RA3RA4

RD0

RD1

Ribbon Cable

Display Board

LEDs (5)

Control Buttons (2)

D0D1D2D3D4

RD2RD3

D0D1

A\CSignal Gnd

ON\OFF

ON\OFF

RB0

RB1

RD2RD3

Signal Gnd

Signal Gnd

ON/OFF

ON/OFF

Signal Gnd

Signal Gnd

Signal Gnd

Heat

A\CSignal Gnd

Signal Gnd

Signal Gnd

VccGnd

VccGnd

120V AC

System GndAC Neutral

Chassis Gnd

Power Conversion Power Conversion DiagramDiagram

Power Conversion

+5V

Gnd

+18V

Fro

m W

all S

ocke

t To R

est of Board

120V AC

System GndAC Neutral

Chassis Gnd

Power Conversion Power Conversion SchematicSchematic

Power Conversion Power Conversion RequirementsRequirements

Provides conditioned power to Provides conditioned power to Signal Conversion BoardSignal Conversion Board

InputsInputs 115 VAC IN115 VAC IN

OutputsOutputs +18 VDC (nominal) OUT+18 VDC (nominal) OUT +5 VDC OUT+5 VDC OUT

Signal Conversion Signal Conversion DiagramDiagramFrom Power Conversion

To

The

rmos

tat 1

To

Microcontroller

Signal Conversion

ON/OFF

ON/OFFDemand 1

Demand 1

Signal Gnd

Signal Gnd

ON/OFF

ON/OFF

Signal Gnd

Signal Gnd

Gnd

+5

VHeat

A\CSignal Gnd

Signal Gnd

Heat

A\CSignal Gnd

Signal Gnd

To

HV

AC

Units

+18

V

Signal Conversion Signal Conversion SchematicSchematic

Signal Conversion Signal Conversion Functional RequirementsFunctional Requirements

InputsInputs Thermostats provide 24 VAC upon DemandThermostats provide 24 VAC upon Demand

2 Heat Inputs2 Heat Inputs 2 Cool Inputs2 Cool Inputs

OutputsOutputs Replaces thermostats to HVAC unitsReplaces thermostats to HVAC units 24 VAC sent to HVAC units via relays based on 24 VAC sent to HVAC units via relays based on

decisions made by microcontroller, I/O Board, or decisions made by microcontroller, I/O Board, or user interfaceuser interface

Optical IsolationOptical Isolation Optocouplers isolate and protect microcontroller Optocouplers isolate and protect microcontroller

& I/O Board from outside 24 VAC circuitry& I/O Board from outside 24 VAC circuitry

Signal ConversionSignal Conversion 24 VAC Input from Thermostats24 VAC Input from Thermostats

Conditioned and rectifiedConditioned and rectified Electrically IsolatedElectrically Isolated Sent to microcontroller & I/O Board Sent to microcontroller & I/O Board

If +5 VDC from microcontrollerIf +5 VDC from microcontroller Amplified via Darlington array to turn off relayAmplified via Darlington array to turn off relay

If 0 VDC from microcontrollerIf 0 VDC from microcontroller Grounds output of Darlington array to turn on Grounds output of Darlington array to turn on

relayrelay 24 VAC Output to HVAC24 VAC Output to HVAC

Sent via closed relaySent via closed relay

Microcontroller Microcontroller SelectionSelection

Name Cyclone II FPGACyclone II FPGA HCS12 87C51 PIC16F747

Part Number EP2C35F672C8N MC9S12UF32 P87C51FB-4N PIC16F747

Producer Altera Freescale NXP Microchip

Recurring Cost $99.70 $4.20 $7.80 $3.20

Package 672-FBGA 64-LQFP 40-PDIP 40-PDIP

Programing Software Quartus II

MGTEK MiniIDE Third Party Bundled with PicKit

Programing Hardware Serial Port Cable USB Cable ZIF Socket + USB PicKit 2

Programing Cost $150.00 $100.00 $110.00 $50.00

Programing Language VHDL Assembly \ C Assembly Assembly \ C

Custom Header Y Y N Y

Timers N Y Y Y

RS-232 N Y Y Y

Internal Clock N N Y Y

Non-Volatile Code N Y Y Y

Notes:

Previous groups FPGA, used in FPGA

class at Vanderbilt

Used in microcontroller

s class at Vanderbilt

Microcontroller currently used in Bonitron Board

Lowest Cost to Project

Microcontroller Microcontroller SelectionSelection

Cyclone II FPGACyclone II FPGA High recurring and non recurring costsHigh recurring and non recurring costs Surface mount with 600+ pinsSurface mount with 600+ pins

HCS12HCS12 Surface mountSurface mount High non recurring costsHigh non recurring costs

87C5187C51 Third party programming softwareThird party programming software No C++ supportNo C++ support

Microcontroller Microcontroller

Controller

5V

Demand 1

Demand 1

Gnd

Vpp

PG

D

PG

C

RxD

TxD

Vcc

RxD

TxD

Gnd

Vpp PGD PGC

RA0RA1RA2RA3RA4

RA0RA1RA2RA3RA4

RD0

RD1

RD2RD3

ON\OFF

ON\OFF

RB0

RB1

RD2RD3

To LE

Ds

(I/O B

oard) F

rom B

uttons (I/O

Board)

To C

omputer (D

B-9)

To R

elays (Signal

Processing

)

From Programming Header

Fro

m P

ower

C

onve

rsio

nF

rom

The

rmos

tats

(S

igna

l Pro

cess

ing)

Development ApproachDevelopment Approach

Programmable microcontroller Programmable microcontroller Internal UART Internal UART Internal timerInternal timer Internal oscillatorInternal oscillator

Compatible with original Compatible with original microcontroller (40 pin DIP)microcontroller (40 pin DIP)

Use PICkit 2 programmer and Use PICkit 2 programmer and development kit to code development kit to code microcontrollermicrocontroller

Development Development MethodologyMethodology

User will write the User will write the application application program in C or program in C or assembly codeassembly code

On-board storageOn-board storage RAMRAM

Configuration Configuration retained as long retained as long as the power is onas the power is on

FlashFlash Store program Store program

code in non code in non volatile memoryvolatile memory

MPLAB IDE Development MPLAB IDE Development SoftwareSoftware

Software provided by Microchip for Software provided by Microchip for programming PIC microcontrollersprogramming PIC microcontrollers

Procedure:Procedure: Write code in assembly languageWrite code in assembly language Program microcontrollerProgram microcontroller Test functionalityTest functionality

Apply test inputs and observe outputsApply test inputs and observe outputs Design test strategy for all possible casesDesign test strategy for all possible cases

MPLAB IDE ScreenshotMPLAB IDE Screenshot

PICkit 2 PICkit 2

Hardware Hardware programmer for PIC programmer for PIC microcontrollersmicrocontrollers

USB programmableUSB programmable Connects via 6 pin Connects via 6 pin

header on PCBheader on PCB Packaged with Packaged with

starter kit for starter kit for testingtesting

ExistingExistingLogicLogic

DiagramDiagram

RS-232RS-232

Graphical user interface for control Graphical user interface for control of overrides and timersof overrides and timers Parallels functionality of previous Parallels functionality of previous

override design override design Replaces variable resistors with Replaces variable resistors with

programmable timing capabilities programmable timing capabilities Allows user to program timers Allows user to program timers

without physically manipulating the without physically manipulating the componentscomponents

Programming RS-232Programming RS-232

GUI done using Visual BasicGUI done using Visual Basic Use feedback loop to perform Use feedback loop to perform

original testingoriginal testing

RS-232 HardwareRS-232 Hardware

Max 232 Max 232 transceiver to transceiver to perform voltage perform voltage conversion conversion between circuitry between circuitry and DB-9and DB-9

Changes voltage Changes voltage range from 0 - 5 range from 0 - 5 VDC to ±15 VDC VDC to ±15 VDC

FloorplanFloorplan

PCB DesignPCB Design Copied 90% from Copied 90% from

previous PCB layoutprevious PCB layout Added connections Added connections

for new for new microcontroller and microcontroller and serial port serial port componentscomponents

2-sided through 2-sided through hole design allows hole design allows easier trace routing easier trace routing than previous single than previous single sided boardsided board

PCB SoftwarePCB Software

Developed PCB design using Developed PCB design using PCBExpressPCBExpress

No License required No License required Order directly though the siteOrder directly though the site Extensive parts libraryExtensive parts library Ability to design custom component Ability to design custom component

based on datasheet specificationbased on datasheet specification

Bottom SideBottom Side

Top SideTop Side

PCB DesignPCB Design

ApprovalApproval

In order to proceed, we request your In order to proceed, we request your approval of the designapproval of the design

Comments?Comments?

Near Term PlanNear Term PlanHardware DevelopmentHardware Development

Add breakpoints to existing PCB Add breakpoints to existing PCB designdesign

Obtain parts from Bonitron Obtain parts from Bonitron storeroomstoreroom

Order PCBOrder PCB Test circuit partitionsTest circuit partitions AssembleAssemble Test Final productTest Final product

Near Term PlanNear Term PlanSoftware DevelopmentSoftware Development

Develop assembly language codeDevelop assembly language code Refine Visual Basic GUIRefine Visual Basic GUI

Hardware ScheduleHardware Schedule

Obtain all components by February Obtain all components by February 1515thth

Order PCB by February 15Order PCB by February 15thth Have assembled prototype boards by Have assembled prototype boards by

March 1March 1stst

Have full board assembled by March Have full board assembled by March 1414thth

Test till design day Test till design day

Software ScheduleSoftware Schedule

Complete GUI by February 22Complete GUI by February 22ndnd Complete programming of the test Complete programming of the test

board microcontroller by March 1board microcontroller by March 1stst Complete programming of product Complete programming of product

ready prototype board ready prototype board microcontroller by March 14microcontroller by March 14thth

System debug and operational testing System debug and operational testing from March 14 until design dayfrom March 14 until design day

http://eecs.vanderbilt.edu/courses/eece295/2007-2008/Bohttp://eecs.vanderbilt.edu/courses/eece295/2007-2008/Bonitron-HVACnitron-HVAC

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