1. Bonitron Air Demand Scheduler Design Review Vanderbilt Senior Design Alex Brown Ajmer Dwivedi Cory Haugh February 04, 2008

2. Introduction Air Demand Scheduler Air Demand Scheduler Reduces peak power consumption Reduces peak power consumption Selects 1 of 2 HVAC units to run at a time Selects 1 of 2 HVAC units to run at a time Allows for manual control using user overrides Allows for manual control using user overrides

3. Objectives Production ready prototype Production ready prototype Low cost microprocessor Low cost microprocessor RS-232 I/O functionality RS-232 I/O functionality Identical logic Identical logic All other specifications are to remain the same All other specifications are to remain the same Preserve existing package Preserve existing package

4. Requirements Input Power Input Power 115VAC, 50/60Hz 115VAC, 50/60Hz Control Signals 24 VAC Control Signals 24 VAC Inputs Inputs Thermostat 1: Air Conditioning 1, Heat 1 Thermostat 1: Air Conditioning 1, Heat 1 Thermostat 2: Air Conditioning 2, Heat 2 Thermostat 2: Air Conditioning 2, Heat 2 Outputs Outputs Unit 1: Air Conditioning 1, Heat 1 Unit 1: Air Conditioning 1, Heat 1 Unit 2: Air Conditioning 2, Heat 2 Unit 2: Air Conditioning 2, Heat 2 Enclosure Enclosure NEMA-12 Wall Mountable w/Quick Release Door Latch (10’’ x 6’’ x 4’’) NEMA-12 Wall Mountable w/Quick Release Door Latch (10’’ x 6’’ x 4’’) Operating Temperature Operating Temperature 0 to +40 Degrees Celsius 0 to +40 Degrees Celsius Storage Temperature Storage Temperature +20 to +65 Degrees Celsius +20 to +65 Degrees Celsius Humidity Humidity Below 90% Below 90% Atmosphere Atmosphere Free of Corrosive Gas and Dust Free of Corrosive Gas and Dust

5. Approach Extract existing design from previous group’s documentation and new hardware Extract existing design from previous group’s documentation and new hardware Replace FPGA development kit with microcontroller Replace FPGA development kit with microcontroller Develop PCB design partitioning circuit components Develop PCB design partitioning circuit components Fabricate assemble and test design Fabricate assemble and test design

6. System Diagram

7. Power Conversion Diagram

8. Power Conversion Schematic

9. Power Conversion Requirements Provides conditioned power to Signal Conversion Board Provides conditioned power to Signal Conversion Board Inputs Inputs 115 VAC IN 115 VAC IN Outputs Outputs +18 VDC (nominal) OUT +18 VDC (nominal) OUT +5 VDC OUT +5 VDC OUT

10. Signal Conversion Diagram

11. Signal Conversion Schematic

12. Signal Conversion Functional Requirements Inputs Inputs Thermostats provide 24 VAC upon Demand Thermostats provide 24 VAC upon Demand 2 Heat Inputs 2 Heat Inputs 2 Cool Inputs 2 Cool Inputs Outputs Outputs Replaces thermostats to HVAC units Replaces thermostats to HVAC units 24 VAC sent to HVAC units via relays based on decisions made by microcontroller, I/O Board, or user interface 24 VAC sent to HVAC units via relays based on decisions made by microcontroller, I/O Board, or user interface Optical Isolation Optical Isolation Optocouplers isolate and protect microcontroller & I/O Board from outside 24 VAC circuitry Optocouplers isolate and protect microcontroller & I/O Board from outside 24 VAC circuitry

13. Signal Conversion 24 VAC Input from Thermostats 24 VAC Input from Thermostats Conditioned and rectified Conditioned and rectified Electrically Isolated Electrically Isolated Sent to microcontroller & I/O Board Sent to microcontroller & I/O Board If +5 VDC from microcontroller If +5 VDC from microcontroller Amplified via Darlington array to turn off relay Amplified via Darlington array to turn off relay If 0 VDC from microcontroller If 0 VDC from microcontroller Grounds output of Darlington array to turn on relay Grounds output of Darlington array to turn on relay 24 VAC Output to HVAC 24 VAC Output to HVAC Sent via closed relay Sent via closed relay

14. Microcontroller Selection Name Cyclone II FPGA HCS1287C51PIC16F747 Part Number EP2C35F672C8NMC9S12UF32P87C51FB-4NPIC16F747 Producer Altera FreescaleNXPMicrochip Recurring Cost $99.70 $4.20$7.80$3.20 Package 672-FBGA 64-LQFP40-PDIP Programing Software Quartus II MGTEK MiniIDEThird PartyBundled with PicKit Programing Hardware Serial Port CableUSB Cable ZIF Socket + USB PicKit 2 Programing Cost $150.00 $100.00$110.00$50.00 Programing Language VHDL Assembly \ CAssemblyAssembly \ C Custom Header Y YNY Timers N YYY RS-232 N YYY Internal Clock N NYY Non-Volatile Code N YYY Notes: Previous groups FPGA, used in FPGA class at Vanderbilt Used in microcontrollers class at Vanderbilt Microcontroller currently used in Bonitron BoardLowest Cost to Project

15. Microcontroller Selection Cyclone II FPGA Cyclone II FPGA High recurring and non recurring costs High recurring and non recurring costs Surface mount with 600+ pins Surface mount with 600+ pins HCS12 HCS12 Surface mount Surface mount High non recurring costs High non recurring costs 87C51 87C51 Third party programming software Third party programming software No C++ support No C++ support

16. Microcontroller

17. Development Approach Programmable microcontroller Programmable microcontroller Internal UART Internal UART Internal timer Internal timer Internal oscillator Internal oscillator Compatible with original microcontroller (40 pin DIP) Compatible with original microcontroller (40 pin DIP) Use PICkit 2 programmer and development kit to code microcontroller Use PICkit 2 programmer and development kit to code microcontroller

18. Development Methodology User will write the application program in C or assembly code User will write the application program in C or assembly code On-board storage On-board storage RAM RAM Configuration retained as long as the power is on Configuration retained as long as the power is on Flash Flash Store program code in non volatile memory Store program code in non volatile memory

19. MPLAB IDE Development Software Software provided by Microchip for programming PIC microcontrollers Software provided by Microchip for programming PIC microcontrollers Procedure: Procedure: Write code in assembly language Write code in assembly language Program microcontroller Program microcontroller Test functionality Test functionality Apply test inputs and observe outputs Apply test inputs and observe outputs Design test strategy for all possible cases Design test strategy for all possible cases

20. MPLAB IDE Screenshot

21. PICkit 2 Hardware programmer for PIC microcontrollers Hardware programmer for PIC microcontrollers USB programmable USB programmable Connects via 6 pin header on PCB Connects via 6 pin header on PCB Packaged with starter kit for testing Packaged with starter kit for testing

22. Existing Logic Diagram

23. RS-232 Graphical user interface for control of overrides and timers Graphical user interface for control of overrides and timers Parallels functionality of previous override design Parallels functionality of previous override design Replaces variable resistors with programmable timing capabilities Replaces variable resistors with programmable timing capabilities Allows user to program timers without physically manipulating the components Allows user to program timers without physically manipulating the components

24. Programming RS-232 GUI done using Visual Basic GUI done using Visual Basic Use feedback loop to perform original testing Use feedback loop to perform original testing

25. RS-232 Hardware Max 232 transceiver to perform voltage conversion between circuitry and DB-9 Max 232 transceiver to perform voltage conversion between circuitry and DB-9 Changes voltage range from 0 - 5 VDC to ±15 VDC Changes voltage range from 0 - 5 VDC to ±15 VDC

26. Floorplan

27. PCB Design Copied 90% from previous PCB layout Copied 90% from previous PCB layout Added connections for new microcontroller and serial port components Added connections for new microcontroller and serial port components 2-sided through hole design allows easier trace routing than previous single sided board 2-sided through hole design allows easier trace routing than previous single sided board

28. PCB Software Developed PCB design using PCBExpress Developed PCB design using PCBExpress No License required No License required Order directly though the site Order directly though the site Extensive parts library Extensive parts library Ability to design custom component based on datasheet specification Ability to design custom component based on datasheet specification

29. Bottom Side

30. Top Side

31. PCB Design

32. Approval In order to proceed, we request your approval of the design In order to proceed, we request your approval of the design Comments? Comments?

33. Near Term Plan Hardware Development Add breakpoints to existing PCB design Add breakpoints to existing PCB design Obtain parts from Bonitron storeroom Obtain parts from Bonitron storeroom Order PCB Order PCB Test circuit partitions Test circuit partitions Assemble Assemble Test Final product Test Final product

34. Near Term Plan Software Development Develop assembly language code Develop assembly language code Refine Visual Basic GUI Refine Visual Basic GUI

35. Hardware Schedule Obtain all components by February 15 th Obtain all components by February 15 th Order PCB by February 15 th Order PCB by February 15 th Have assembled prototype boards by March 1 st Have assembled prototype boards by March 1 st Have full board assembled by March 14 th Have full board assembled by March 14 th Test till design day Test till design day

36. Software Schedule Complete GUI by February 22 nd Complete GUI by February 22 nd Complete programming of the test board microcontroller by March 1 st Complete programming of the test board microcontroller by March 1 st Complete programming of product ready prototype board microcontroller by March 14 th Complete programming of product ready prototype board microcontroller by March 14 th System debug and operational testing from March 14 until design day System debug and operational testing from March 14 until design day

37. http://eecs.vanderbilt.edu/courses/eece295/2007-2008/Bonitron-HVAC Our webpage: