3DP CDR

1
3DP CDR

• Joel Meisinger
• Harout Hedeshian
• Frankie Ning
• Dominic Boiko
• Ching-Han Tseng

2
3DP Overview

• Design of a 3D printer for affordable
  prototyping.
• Prints each cross section of a 3D object layer by
  layer
• Three axis motion in a 2x2 feet chassis for large
  scale modeling
• Use of accurate stepping motors for high
  precision printing
• Network communication

D
Inputs
Outputs
3D prototype
Job File
3
P
User Controls
Status
3
Levels of Objective

• Low Level
• Position printer head from basic raw commands
• Layout material
• Display printer status
• Mid Level
• Print Simple 3D objects
• Position Feedback
• High Level
• Print objects base on STL job files
• Independent power system

• Printer Objective Resolution
• 25mm/s linear write speed
• 0.5mm deposition resolution
• 5mm3/s (0.3 in3/s)
• Capable of printing a 10cm3 object
• Capable of printing functional prototypes

4
Electrical System Functional Block Diagram
Interrupt
Electrical Power System
Command and Data Handling
RS422 Bus
Stepper Motor Controller
Position Sensing Controller
Material DepositionController
I/O
Power
RS422
Interrupt
GPIO
5
EPS

• Electrical Power System

6
Power Supply

• Provide each sub-system with appropriate power
  level
• Isolated Power System
• Reduced Shock Hazard
• Continuity of power
• Noise Reduction
• Open and short circuit protection
• Function Decomposition
• Transformer Design

7
EPS FBD
Wall Outlet 120VAC
EMI Filter
CDH
5V Forward converter (Isolated)
Feedback
MDC
Rectifier Bridge
Transformer/Reset Winding
Isolated
PSC
12V Forward converter (Isolated)
FPS
SMC
Metallic Enclosure For Grounding
Relay(Enable)
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(No Transcript)
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Protection

• Open Circuit
• Snubber Circuit will be implemented by the
  transformer and output to
• prevent inductive kick effect.
• Bleed Resistor for discharging capacitor and
  prevent OC.
• Short Circuit (FPS IC)
• Latch Mode Protection FPS shuts down SMPS till
  AC power is reconnected
• Auto Restart Mode Protection Under Voltage
  Lockout(UVLO)
• Other
• Overload Protection
• Over Voltage/Current Protection
• Metallic enclosure grounding

10
Function Decomposition
Module EMI Filter
Inputs 120VAC from Wall outlet
Outputs 120VAC to Rectifier
Functionality The process that filters out high frequency noises comes in from the wall outlet. EMI dedicates a return-path especially for noises, and therefore greatly reduces the unwanted spike when proceeds.
Module Full-Wave Rectifier Bridge
Inputs EMI Filter
Outputs 170VDC with approximated voltage ripple to FPS
Functionality The function that generates full positive waves. The smoothing capacitor, locates at the output of the rectifier, converts the full-wave rippled output of the rectifier into a smooth DC output voltage.
Module FPS (Power Switch)
Inputs 170VDC from Rectifier, Isolated Feedback from output
Outputs Primary, Reset, Vcc and Secondary windings on the transformer
Functionality The FPS has the internal switching frequency of 67KHz on MOSFET to makes DC-DC converter. It requires about 15VDC on Vcc winding to drive the chip and startup various functions.
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Function Decomposition Cont.
Module Transformer
Inputs FPS
Outputs 5VDC, 12VDC Converter
Functionality Base on the turn ratio on the windings, this module may step up or down on voltage
Module DC-DC converter
Inputs Transformer
Outputs 5VDC, 12VDC rail to each subsystems
Functionality With manipulations on passive parts, these modules output desired voltage rail and current.
Module Feedback
Inputs 5VDC, 12VDC rails
Outputs FPS
Functionality This module supplies or reduce amount of gains to stabilize the output in case of any drastic changes.
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Transformer Design
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Risk/Goal

• Primary risk
• Hand-made Transformers might not operate as ideal
  as the calculation
• Fall back to more detailed analysis, calculation,
  component upgrade, and proper
• circuit protection
• Over-current/short current protection, metallic
  enclosure grounding and isolation
• are part of considerations to prevent this
  hazard
• Goal
• Redesign Transformer and find the better ferrite
  core
• Fully test out the circuits on the perf-board
• Power management
• Proper debug/Test procedures documented
• PCB

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CDH

• Command and Data Handling

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Command Data Handling

• Coordinate all events on printer
• Communications interface for daughter boards
• Provide a physical human interface for high level
  control
• Platform independent and driverless
  communications to host computer

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Not populated on Rev A
EPS
DEBUG
Power Sequencing
RS232
SRAM Data Buffer
5V
5-gt3.3 Buck
5-gt2.5 Buck
RS422 Driver
6-DIN
ARM Cortex M3 (Stellaris LM3S6965) Main CPU
SPI 4Mb
AVR MCU (ATXMEGA128A1) IO Hub
RS422 Driver
6-DIN
RS422 Driver
6-DIN
RS232
CY8C9560A GPIO Expander
Ethernet
Reset lines
I2C
GPIO
GPIO
USB-gtRS232
LCD
Buttons
Buzzer
Not populated on Rev A
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Functional Compost
Module AVR MCU
Inputs COM from CDH, I2C from CY8C9560A, COM(0-3)
Outputs COM to CDH, I2C to CY8C9560A, COM(0-3)
Functionality Responsibly for ensuring reliable message packet delivery between all subsystems. Also relay button presses and sends back to CDH
Module Buck Converters
Inputs 5VDC
Outputs 3.3VDC, 2.5VDC
Functionality Take 5V from the power bus and step it down to 3.3V and 2.5V noting the correct power up sequence.
Module ARM Cortex M3 LM3S9595
Inputs USB, Ethernet, COM from AVR
Outputs LCD, COM to AVR
Functionality Primary processor on 3DP responsible for interfacing 3DP to the real world. Process vectors and coordinate subsystems.
Module CY8C9560A
Inputs I2C from AVR MCU, Buttons
Outputs I2C to AVR MCU, Buzzer
Functionality Encodes buttons and drives buzzer. I wanted to play with this chip.
Module SRAM Buffer
Inputs Address, Data
Outputs Data
Functionality Space to store circular buffers of packet data for relay and transmission, and retransmission
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Electrical
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Board level firmware

• Stellaris
• FreeRTOS
• uIP
• Web server
• Using a highly modified Telnet server
  implementation to provide raw TCP socket for
  communication.

• XMEGA
• Mostly interrupt driven custom firmware
• Simple functionality acting as a smart I/O
  controller.
• Nobody has ported an RTOS to the XMega?!

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ARM Firmware
RTOS Kernel Managed Tasks
Interrupts
uIP
LCD Message Queue
MAC Management
System Tick
HTTPD
TELNET
Ethernet
Shell/Protocol
USB/UART
Lots of Cool Blinking LEDs
Event Dispatch
COM
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AVR Firmware
Main Loop
Interrupts
LED Management
System Tick
COM1
Message Routing
Keypad
COM2
COMV1 AVR Management
COM3
COM4
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Risk

• Original risks from PDR
• Primary risk Ethernet non-functional
• Working
• Secondary Risk USB-UART non-functional
• Working
• New risks
• Getting bored and making LEDs blink in funny
  patterns

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MDC

• Material Deposition Controller

Joel Meisinger
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Material Deposition Controller

• Objective
• Keep constant print head tip temperature
• Keep constant torque on fed printing material
• Requirements
• Supply consistent material delivery to the
  printing area(.5mm diameter /- .1mm)
• Be able to start and stop printing material
  reliably.
• Notify CDH(main system) when print head is up to
  temperature and ready to print or when the
  printer out of material.

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MDC Schematic
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MDC Functional Block Diagram
EPS
RS232 Debug
MDC
XMEGA MCU
CDH
3.3V DC/DC converter
RS422 Driver
5V
Deposition Motor Driver
Deposition Thermal Driver
5V DC/DC converter
12V
Micro data lines
Power
Print head control
Print head
Thermal Feedback
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MDC Hardware Functional Decomposition
Module XMEGA MCU
Inputs 3.3V, DGND, RS422 TX(CDH), Thermal feedback
Outputs RS422 RX(CDH), Motor Driver, Thermal driver
Functionality Controller for the material deposition unit/print head. Regulates temperature and constant torque for the material feed.
Module 3.3V DC/DC Converter
Inputs 5V supplied from EPS, DGND
Outputs 3.3V
Functionality Provides power for Xmega MCU and drive signal to motor driver controller. Low current requirement.
Module 5V DC/DC Converter
Inputs 12V supplied from EPS, AGND
Outputs 5V
Functionality Provides power to motor driver controller/stepper motor. High current requirement.
Module Thermal Driver
Inputs 12V, AGND, drive signal
Outputs PWM Power to the print head nozzle.
Functionality Drives the heater on the print head.
Module RS232 Driver
Inputs Xmega TX and PC TX, DGND
Outputs Xmega RX and PC RX
Functionality Debug port for Xmega and development environment.
Module Motor Driver
Inputs 5V, AGND, drive signal
Outputs Stepper motor driving signal.
Functionality Drives the motor to feed the deposition material.
Module RS422 Driver
Inputs Xmega TX and PC TX, DGND
Outputs Xmega RX and PC RX
Functionality Communication driver between CDH and XMEGA for drive commands.
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MDC Software
MDC
Main
Init_sys()
Packet Handlers
LED
Temp Sensor
Motor Drive
PWM Temp Drive
Init_CLK() Init_IO_PIN() Init_USART_RS232 Init_USA
RT_RS422 Init_Timer0( )
read_packet() write_packet()
LED_On() LED_Off()
SM_Drive() QDEC_EVSYS() QDEC_Index()
adc_read()
PWM_Rate(.)
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Print-head and Material Specifications

• Print-head is completely custom.
• Thermal controlled brass tip heated by NiChrome
  wire at temperatures 221F - 300F
• ABS plastic Possesses outstanding impact
  strength and high mechanical strength making it
  well suited for working mechanical parts.
• Stepper motor with feed gear that will supply
  constant torque(TBD).
• Compact having the ability to adapt to most 3d
  axis systems. 12 square inches.

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Risk/Contingency Plan

• ABS not working for dependable deposition
• Nozzle tip temperature not constant
• Use other material type such as a PVC or epoxy
  resin. Also try a variable torque routine that
  will be suited for changing speed and direction
  of the print-head when moving from one vertices
  to another.
• Use other tip sizes, apertures and heater
  materials.

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PSC

• Position Sensor Controller

Frankie Ning
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Position Sensor Controller

• Objective
• Keep track of extruder head location
• Keep track of motor movements and provide limit
  warnings
• Keep track of temperature on stepper motors and
  motor driver heat sinks
• Requirements
• Supply CDH Controller with 3 axis position of the
  extruder within 1/200th of a rotation
• Supply motor status to CDH Controller
• Supply limit warnings and movement verification
  to Stepper Motor Controller

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PSC Schematic
34
PSC Functional Block Diagram
EPS
CDH
RS422
PSC
ISP
RS232
RS422 Driver
6 GPIO
RS232 Driver
SMC
2 Limit X
XMEGA MCU
3.3V DC/DC converter
2Limit Y
5V
2 Limit Z
5V
Encoder X
Encoder Y
Encoder Z
Motor Temp XYZ
3.3V
GPIO
ADC
USART
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Hardware Functional Decomposition
Module XMEGA MCU
Inputs 3.3V, GND, RS232 TX(PC), RS422 TX(CDH), Encoder A,B, index signals from Encoder X,Y,Z, ISP
Outputs ISP, RS232 TX(PC), RS422 TX(CDH)
Functionality Gathers data from limit, temperature, and encoder sensors. Controls the RS232 and RS422 driver to communicate with the PC or CDH. Also includes GPIO to SMC for temperature and limit warnings
Module Encoder X,Y,Z
Inputs Rotary disc in encoder
Outputs Quadrature A and B, 90o off phase
Functionality keep track of motor movement and position
Module Limit X,Y,Z
Inputs Limit flag
Outputs Quadrature A and B, 90o off phase
Functionality keep track of motor movement and position
Module ISP
Inputs PDI_CLK, PDI_RESET, power, ground
Outputs PDI_Data,
Functionality AVRISP MkII Programming module for Xmega
Module Motor Temp X,Y,Z
Inputs Temperature sensor mounted on stepper motor
Outputs Analog output 200mV 1.75V at 10mV/oC
Functionality keep track of motor temepratures
Module RS422 Driver
Inputs Xmega TX and CDH TX
Outputs Xmega RX and CDH RX
Functionality Communication driver between CDH and PSC, command and data is sent using the RS422 driver
Module 3.3V DC/DC Converter
Inputs 5V
Outputs Regulated 3.3V
Functionality supply power to on board ICs
Module RS232 Driver
Inputs Xmega TX and PC TX
Outputs Xmega RX and PC RX
Functionality Communication driver between PC RS232 and XMEGA UART
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Software
PSC
Main
Init_sys()
Packet Handlers
LED
Temp Sensor
Encoder
Limit
Init_CLK() Init_IO_PIN() Init_USART_RS232 Init_USA
RT_RS422 Init_QDEC( ) Init_Timer0( )
read_packet() write_packet()
toggle_ heartbeat()
QDEC_Direction() QDEC_EVSYS() QDEC_Index()
adc_read()
Limit_detect()
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Encoder Specifications

• US-Digital E5
• Optical Rotary Encoder
• Index
• Quadrature
• 512 CPR (cycles per revolution)
• 2048 PPR (pulses per revolution)
• Max detectable rpm 11718
• Fits ACME threaded rod
• 2mm 10mm or 1/8 3/8 shaft
• Max Frequency Response 100kHz

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Risk/Concerns

• Limited Funding
• Remove Encoders, reduce cost
• Not critical to design/ Good to have feedback
• Stepper motors with fine resolution
• Minimum cost PSC would include
• Temperature Sensor
• Track temperature of motors and drivers
• Photointerrupt Sensor
• Detect when print head moves to a X, Y, or Z axis
  limit
• Apply to EEF
• Personal donation

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SMC

• Stepper Motor Controller

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Stepper Motor Controller

• Objective
• Control motion of extrude head along 3 axis
  (X,Y,Z)
• Control speeds of motors using constant current
  motor drivers
• Accurate positional translations using high
  resolution stepper motors as opposed to simple DC
  motors
• Requirements
• Drive steppers motors based on instructions given
  by CDH controller
• Provide current motor status when queried by CDH
• Able to drive motors accurately with enough
  torque to control extrude head position

41
SMC Functional Block Diagram
EPS
SMC
ISP
RS232
PSC
6 GPIO
RS232 Driver
XMEGA MCU
CDH
3.3V DC/DC converter
RS422 Driver
5V
RS422
Motor Driver
Motor Driver
Motor Driver
Legend 12V 5V 3.3V GPIO Isolated Signals UART
Linear Actuator X
Linear Actuator Y
Linear Actuator Z
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Top Level
43
Functional Decomposition - Hardware
Module RS232 Driver
Inputs Xmega TX and PC TX
Outputs Xmega RX and PC RX
Functionality Communication driver between PC RS232 and XMEGA UART
Module ISP
Inputs PDI_CLK, PDI_RESET, power, ground
Outputs PDI_Data,
Functionality AVRISP mkII Programming module for Xmega
Module XMEGA MCU
Inputs 3.3V, DGND, RS232 TX(PC), RS422 TX(CDH), ISP, PSC limit sense GPIO
Outputs ISP, RS232 TX(PC), RS422 TX(CDH), Motor Driver Control Signals
Functionality Communication driver between PC RS232 and XMEGA UART, Configure motor driver operation
Module Motor driver TB65605AHQ
Inputs 5V, 12V, AGND, motor driver control signals
Outputs PWM current waveform for 2 phase stepper motor
Functionality Take digital control signals and drive a single stepper motor and defined torques, speeds, and resolution.
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Choosing TB6560AHQ

• Single 2-phase bipolar motor driver chip
• Controllable current for torque management
• Capable of half stepping and microstepping
• Digital control inputs
• Stepping speed determined by input clock
• Success!!!

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TB6560AHQ full step signals
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Software Block Diagram
SMC
Main
init_sys()
Packet Handler
Motor controller
Init_CLK() Init_IO_PIN() Init_USART_RSxxx() Init_T
imer0( )
read_packet() write_packet() execute()
Check limits Set control signals
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Function Decomp-Software
Module Main
Inputs None.
Outputs None.
Functionality Call init_sys() to bring XMEGA online. Call read_packet() and write_packet() for interboard communications. Call execute() on commands received from CDH. Call the motor driver handling functions.
Module Init_sys()
Inputs None.
Outputs None.
Functionality Initializes the clock, IO pins, USARTs, and timers.
Module Packet Handler
Inputs Packet by serial (see struct for packet)
Outputs Response packet
Functionality The packet handler will read bytes from the serial communication and construct a packet based off our defined protocol. Also execute any commands sent in the packet.
Module Motor Controller
Inputs Limit sense GPIO from PSC. Motor axis states for control signals (see motor_driver struct)
Outputs Control signals to the motor drivers.
Functionality Sets the control signals to the motor drivers based on each motor axis current state as defined by the motor_driver struct. Stop motion and alert CDH when limits of motors have been reached.
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Structs

• // Packet struct
• typedef struct
• uint8_t to
• uint8_t from
• uint8_t size
• uint8_t proto_ver
• uint8_t reserved_byte_4
• uint8_t payload32
• packet

• // motor_driver struct
• typedef struct
• uint8_t tq1
• uint8_t tq2
• uint8_t dcy1
• uint8_t dcy2
• uint8_t m1
• uint8_t m2
• uint8_t cw_ccw
• //uint8_t clk //possibly implemented as a
  single line to all motors
• uint8_t reset
• uint8_t en
• motor_driver

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Changes of design from PDR

• Optoisolators required more current in order to
  operate with our desired bandwidth
• XMEGA cant supply enough current
• Added MOSFETs to supply the required current
• Using part DMN601DMK-7 (dual N-channel MOSFET)
• Risks Motor driver chips are out of stock
• Have just enough for final revision
• Possibly able to get more by end of October
• Placed order (backordered, estimated ship date
  10/20)
• If not available will need to redesign motor
  driver controller
• Most likely on MDC, only uses 1 motor driver,
  easier to change
• Alternative motor drivers are available and in
  consideration
• Smaller versions of current motor driver
  sufficient for MDC
• In other words there is no more hardware risks
• Software is already partially implemented and
  works with hardware

50
PDR update

• Schedule
• Maintaining with schedule
• SMC is ahead of schedule
• Original goal have flashing LEDs (complete)
• Current status stepper motor driving capability
  tested and working
• Most configuration signals tested
• (need to test decay mode)
• Current goal
• establish packet handling (started)
• Design motor driver handling firmware

51
SYSTEM
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Division of Labor
Task Ching Dominic Frankie Harout Joel
CDH Secondary Secondary Primary
EPS Primary Secondary Secondary
MDC Secondary Secondary Primary
PSC Secondary Secondary Primary
SMC Primary Secondary Secondary
Mechanical Secondary Primary Secondary Primary Primary
User Interface Primary Secondary Secondary
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Progress Update

• MDC
• Blinking LEDs
• PSC
• Timer interrupt driven LEDs
• RS422
• Temperature sensor data sent to PC
• Limit Sensor (toggle LED)
• SMC
• Blinking LEDs
• Driving stepper motors
• RS422

• CDH
• LCD display
• RS422
• USB
• Ethernet
• EPS
• First Sage AC Power and EMI Filter
• Second stage Rectifier working (not transformer)

54
Schedule

• Gant chart

55
Financial/Expenses
Expense Breakdown Expense Breakdown
Subsystem Total
CDH 246
SMC 273
PSC 251
MDC 250
EPS 200
Mechanical 151
Development Kits 310
Board Order 495
Total 2176
Item Name Description Unit Price Quantity Total Amount
STR-MTR-17048 Stepper Motors 19.00 3 57
ATSTK600 STK 600 development kit 206.96 1 206.96
ATSTK600-TQFP64-2 STK600 socket adapter 102.96 1 102.96
LM3S6965 CORTEX MCU 15.29 2 30.58
ATXMEGA128A1-AU XMEGA MCU 10.2 2 20.40
ATXMEGA64A-AU XMEGA MCU 8.21 8 65.68
MCP9700A-E/To Temperature Sensors 0.34 5 1.70
GP1S53VJ000F Photo-interrupt Sensors 0.85 3 2.55
E5 USDIGITAL Optical Encoders 62.32 3 62.32
LTV-846S Optocouplers 0.73 25 18.25
FAN8303 DC/DC Converter 1.12 25 28.00
B230A Schottky Diodes 0.413 14 5.78
DN759x Inductors 2.73 5 23.76
ASV-xxxxxMHZ Oscillator 2.63 10 26.30
TB6560 Stepper Motor Driver 4.73 5 23.65
ADM3071EARZ RS422 Driver 3.4 10 34.00
DMN601DMK N-CH MOSFET 0.61 20 12.32
GBU6J-BPMS Rectifier bridge 1.4 3 4.20
FS7M0880YDTU PWM Switching Reg 3.64 4 14.56
ACM9070-701 Common Mode Choke 1.58 2 3.16
598-8710-307F LED 2.17 10 21.70
1N400xDICT-ND Rectifier 0.31 8 10.52
WK6249 Fuseholder 1.88 2 3.76
FOD817A High power Optocoupler 0.5 4 2
M9975 High power Inductor 3.47 3 10.41
ASM69AC Linear slide 766.00 1 766.00
C0816X7R1Cxxxx Passive Capacitors 0.03 1000 30
ERJ-3GEYxxx4V Passive Resistors 0.03 1000 30
161-2306 Mini-DIN connectors 0.93 10 9.3
A35109 DB9 Connectors 0.95 4 3.8
Cat5e/ PS2/ DB9/ USB Cables 41.53 1 41.53
EE80251S3-0000 Fan 3.27 1 3.27
EPS/SMC/PSC/MDC 2 Layer PCB 33 8 264
CDH 4 Layer PCB 66 2 132
Total 2175.522
Financial Support Financial Support
UROP 1000
Halleck Willard Inc. 826
ECEE Department 367
Total 2193
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Expected Milestone Goals

• Milestone 1

• milestone2

• Blinking (naked eye) LEDs on SMC, MDC, PSC, CDH
• Display functional interboard communication on
  RS422
• Display one temperature reading on Realterm
  through RS232
• Display one limit sensor by turning off LED when
  limit sensor is triggered
• Drive one motor via command from CDH
• Ready for Revision B board orders

• Display Encoders data via RS232 or CDH
• Direction
• Position
• Display valid C3DP defined protocols via logic
  analyzer for SMC, MDC, PSC, CDH

57
Questions?