SEP Step 5: Detailed Design

Added by Aaron Harper over 11 years ago

EPS Detailed Design

Introduction

While the preliminary design is nearly a complete detailed design, the PCB design needs to be completed before assembly can begin. This will be completed while parts are on order, as some have a 2-3 week lead time in the quantities required.

Design Criteria Review

  • EPSRR 1.1 The EPS board uses a Texas Instruments MSP430 microcontroller to measure and store the sensor data
  • EPSRR 1.2 the EPS board is made from components which are rated beyond the specification as listed, and the system will operate without direct intervention by an operator.
  • EPSRR 2.1 The EPS board is designed in such a way that it may be installed by any person with solar power or electrical wiring experience.
  • EPSRR 2.2 The EPS board will have screw holes to mount the board using #10 screws. Alternatively, a DIN rail clip may be used.
  • EPSRR 2.3 The EPS board can draw it's power from either monitored load or from another 6-30VDC source.
  • EPSRR 3.1 The EPS board shall measure predefined parameters.
    • EPSRR 3.1.1 The EPS board measures the ambient temperature in the enclosure using a sensor on the board.
    • EPSRR 3.1.2 The EPS board measures voltages of two separate circuits directly with a chip that has built in isolation.
    • EPSRR 3.1.3 The EPS board limits the input voltage to the sensor to safe levels using a zener and current limiter.
    • EPSRR 3.1.4 The EPS board measures the current of two separate circuits using a directly with a chip that has built in isolation.
  • EPSRR 3.2 The EPS board transmits measurement data or fault conditions to the server using a MAC chip with full TCP/IP stack.
    • EPSRR 3.2.1 The EPS board will transmit measurement data on demand (web page request).
    • EPSRR 3.2.2 The EPS board will be capable of transmitting measurement data on a schedule (FTP or email).
  • EPSRR 4.1 The EPS board consumes minimal power. Design maximum is 24mW.
  • EPSRR 4.2 See EPSRR 2.3.
  • EPSRR 4.3 The EPS board meets all criteria in this area, having a tolerance for massive overvoltage and 12 bit accuracy.
  • EPSRR 4.4 The EPS board measures temperature within from -20 to 85C with 12 bit accuracy.
  • EPSRR 4.5 The EPS board meets all criteria in this area, having a tolerance for massive overcurrent and 12 bit accuracy.
  • EPSRR 4.6 The EPS board meets all criteria in this area, having a MAC controller IC with a fully functional TCP/IP stack and Ethernet Jack with Magnetics.
  • EPSRR 6.1 The EPS board is read using standard web protocols which are standardized across all platforms.
  • EPSRR 6.2 The EPS board uses standardized connections including Screw terminals and Ethernet.
  • EPSRR 8.1 The EPS board is optimized for ease of production.
  • EPSRR 8.2 See ESPRR 8.1.
  • EPSRR 9.2 The production units appear to cost around $60.00 in parts.
  • EPSRR 11.4 Attention has been paid into the durability of the design to keep waste to an absolute minimum.

Block Diagram

Schematic

Bill Of Materials

Schematic Description Package
C1 68uF Capacitor SMD
C2 120uF Capacitor Axial
Cf1 1uF capacitor SMD
Cf2 1uF capacitor SMD
D1 1N5817 Schottky diode SMD
L1 100uH Inductor SMD
Ra1 47k Ohm .25W Resistor SMD
Rb1 47k Ohm .25W Resistor SMD
Rb2 47k Ohm .25W Resistor SMD
Rf1 4.7 Ohm .25W resistor SMD
Rf2 4.7 Ohm .25W resistor SMD
Rf3 4.7 Ohm .25W resistor SMD
Rf4 4.7 Ohm .25W resistor SMD
RL1 180 Ohm .5W resistor SMD
RL2 180 Ohm .5W resistor SMD
Rs1 068 Ohm 10W resistor Axial
Rs2 068 Ohm 10W resistor Axial
U1 LM2594M-3.3/NOPB Voltage regulator SSOP-8
U2 TMP102 Temp sensor (I2C) SSOP-6
U3 INA226 Current and voltage sensor SSOP-10
U4 INA226 Current and voltage sensor SSOP-10
3 position jumper block Std
5mm barrel jack, 2.1mm center pole Std
8 position screw terminals Std
Populated Ethernet Booster Pack (MSP430 MCU) Board
EPS PC board Board

Budget

Schematic Description Prototype Cost Production Cost
C1 68uF Capacitor $.49 $1.15
C2 120uF Capacitor $0.62 $0.62
Cf1 1uF capacitor $0.14 $1.15
Cf2 1uF capacitor $0.14 $1.15
D1 1N5817 Schottky diode $0.27 $0.19
L1 100uH Inductor $0.18 $0.09
Ra1 47k Ohm .25W Resistor $0.37 $0.03
Rb1 47k Ohm .25W Resistor $0.37 $0.03
Rb2 47k Ohm .25W Resistor $0.37 $0.03
Rf1 4.7 Ohm .25W resistor $0.37 $0.03
Rf2 4.7 Ohm .25W resistor $0.37 $0.03
Rf3 4.7 Ohm .25W resistor $0.37 $0.03
Rf4 4.7 Ohm .25W resistor $0.37 $0.03
RL1 180 Ohm .5W resistor $0.37 $0.03
RL2 180 Ohm .5W resistor $0.37 $0.03
Rs1 068 Ohm 10W resistor $2.14 $2.14
Rs2 068 Ohm 10W resistor $2.14 $2.14
U1 LM2594M-3.3/NOPB Voltage regulator $2.70 $2.70
U2 TMP102 Temp sensor (I2C) $5.95 $1.69
U3 INA226 Current and voltage sensor $6.33 $3.38
U4 INA226 Current and voltage sensor $6.33 $3.38
3 position jumper block $.22 $.13
5mm barrel jack, 2.1mm center pole $4.95 $1.12
8 position screw terminals $2.45 $2.45
Populated Ethernet Booster Pack (MSP430 MCU) $25.00 $25.00
EPS PC board (in qty. 10) $0.00 $12.00
Subtotal $58.21 $60.75
Labor $1762.50 $135.52
TOTAL $1820.71 $196.27

Note: this budget reflects 8 hours of PCB layout which will be complete by 25 FEB 2013

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Replies (3)

RE: SEP Step 5: Detailed Design - Added by Jeremy Wright over 11 years ago

You've done this differently than we did on Shepard, and I think it's something that we should talk about during the next Shepard documentation meeting.

RE: SEP Step 5: Detailed Design - Added by Aaron Harper over 11 years ago

I did... but that's because of the specific situation. As you may have guessed, I skipped a lot of the prelim work, moving straight into production for the most part. Also, the mechanicals of the design are also much simpler than Shepard, since the project is purely electronic. At this point I need go/no go from the client to proceed to ordering and assembly, so this is as good as a point to do it as any.

This abbreviated process probably shouldn't be followed in a large multi-discipline project.

RE: SEP Step 5: Detailed Design - Engineering Change - Added by Aaron Harper over 11 years ago

Power/Temp Monitor and Control System (EPS/ECLSS) Detailed Design

Introduction

This is a temperature and power monitoring system for the radio/battery cabinets on wireless internet service providers (WISP) repeaters. Other uses of this project are satellite and HAB payloads. Attention will be paid to make the project multi-role, but not at the expense of the primary stakeholders (WISPs). The PCB design needs to be completed before assembly can begin. This will be completed while parts are on order, as some have a 2-3 week lead time in the quantities required.

Design Criteria Review

  • EPSRR 1.1 The EPS board uses a Texas Instruments MSP430 microcontroller to measure and store the sensor data
  • EPSRR 1.2 the EPS board is made from components which are rated beyond the specification as listed, and the system will operate without direct intervention by an operator.
  • EPSRR 2.1 The EPS board is designed in such a way that it may be installed by any person with solar power or electrical wiring experience.
  • EPSRR 2.2 The EPS board will have screw holes to mount the board using #10 screws. Alternatively, a DIN rail clip may be used.
  • EPSRR 2.3 The EPS board can draw it's power from any 6-30VDC source.
  • EPSRR 3.1 The EPS board shall measure predefined parameters.
    • EPSRR 3.1.1 The EPS board measures the ambient temperature in the enclosure using a sensor on the board.
    • EPSRR 3.1.2 The EPS board measures voltages of two separate circuits directly with a chip that has built in isolation.
    • EPSRR 3.1.3 The EPS board limits the input voltage to the sensor to safe levels using a zener and current limiter.
    • EPSRR 3.1.4 The EPS board measures the current of two separate circuits using a directly with a chip that has built in isolation.
  • EPSRR 3.2 The EPS board transmits measurement data or fault conditions to the server using a MAC chip with full TCP/IP stack.
    • EPSRR 3.2.1 The EPS board will transmit measurement data on demand (web page request).
    • EPSRR 3.2.2 The EPS board will be capable of transmitting measurement data on a schedule (FTP or email).
  • EPSRR 4.1 The EPS board consumes minimal power. Design maximum is 24mW.
  • EPSRR 4.2 See EPSRR 2.3.
  • EPSRR 4.3 The EPS board meets all criteria in this area, having a tolerance for massive overvoltage and 12 bit accuracy.
  • EPSRR 4.4 The EPS board measures temperature within from -20 to 85C with 12 bit accuracy.
  • EPSRR 4.5 The EPS board meets all criteria in this area, having a tolerance for massive overcurrent and 12 bit accuracy.
  • EPSRR 4.6 The EPS board meets all criteria in this area, having a MAC controller IC with a fully functional TCP/IP stack and Ethernet Jack with Magnetics.
  • EPSRR 6.1 The EPS board is read using standard web protocols which are standardized across all platforms.
  • EPSRR 6.2 The EPS board uses standardized connections including Screw terminals and Ethernet.
  • EPSRR 8.1 The EPS board is optimized for ease of production.
  • EPSRR 8.2 See ESPRR 8.1.
  • EPSRR 9.2 The production units appear to cost around $85.00 in parts.
  • EPSRR 11.4 Attention has been paid into the durability of the design to keep waste to an absolute minimum.

Block Diagram

Schematic

Bill Of Materials

Control Board
Schematic Description Package
C1 68uF Capacitor SMD
C2 120uF Capacitor Axial
D1 1N5817 Schottky diode SMD
L1 100uH Inductor SMD
Rb1 47k Ohm .25W Resistor SMD
Rb2 47k Ohm .25W Resistor SMD
U1 LM2594M-3.3/NOPB Voltage regulator SSOP-8
CN1 Molex70555-0038 Locking connector thru hole
CN2 Molex70555-0038 Locking connector thru hole
CN3 Molex70555-0038 Locking connector thru hole
CN4 Molex70555-0038 Locking connector thru hole
CN5 Molex70555-0038 Locking connector thru hole
J1 5mm barrel jack, 2.1mm center pole Std
EPS Board (MSP430 MCU and MAC IC) Board
Current Sensor Board
Schematic Description Package
CN1 Molex70555-0038 Locking connector Thru hole
Cf1 1uF capacitor SMD
2 position screw terminals Std
Rf1 4.7 Ohm .25W resistor SMD
Rf2 4.7 Ohm .25W resistor SMD
RL1 220 Ohm .5W resistor SMD
Rs 3.9 mOhm 5W resistor Axial
Ra1 47k Ohm .25W Resistor SMD
Ra2 47k Ohm .25W Resistor SMD
S1,2 2 pos DIP switch Thru hole
U3 INA226 Current and voltage sensor SSOP-10
Current Sensor PC Board Board
Molex 50-57-9404 (mating connector for cable) Cable
Molex 50-57-9404 (mating connector for cable) Cable
Alpha Wire 1174c SL005 4cond 22ga Cable
Temperature Sensor Board
Schematic Description Package
CN1 Molex70555-0038 Locking connector Thru hole
U2 TMP102 Temp sensor (I2C) SSOP-6
Temperature Sensor PC Board Board
Molex 50-57-9404 (mating connector for cable) Cable
Molex 50-57-9404 (mating connector for cable) Cable
Alpha Wire 1174c SL005 4cond 22ga Cable

Preliminary Budget

Control Board
Schematic Description Prototype Cost Production Cost
C1 68uF Capacitor $0.49 $1.15
C2 120uF Capacitor $0.62 $0.62
D1 1N5817 Schottky diode $0.27 $0.19
L1 100uH Inductor $0.18 $0.09
Rb1 47k Ohm .25W Resistor $0.37 $0.03
Rb2 47k Ohm .25W Resistor $0.37 $0.03
U1 LM2594M-3.3/NOPB Voltage regulator $2.70 $2.70
CN1 Molex70555-0038 Locking connector 0.97 $0.96
CN2 Molex70555-0038 Locking connector $0.97 $0.96
CN3 Molex70555-0038 Locking connector $0.97 $0.96
CN4 Molex70555-0038 Locking connector $0.97 $0.96
CN5 Molex70555-0038 Locking connector $0.97 $0.96
J1 5mm barrel jack, 2.1mm center pole $4.95 $1.12
EPS Board (MSP430 MCU and MAC IC) $0.00 $12.00
Populated Ethernet Booster Pack (MSP430 MCU) $25.00 $25.00
Labor $1,362.50 $120.12
SUBTOTAL $1,402.30 $167.85
Current Sensor Board
Schematic Description Prototype Cost Production Cost
CN1 Molex70555-0038 Locking connector $0.97 $0.96
Cf1 1uF capacitor $0.14 $1.15
Phoenix Contact 1714971 two position screw terminals $1.34 $1.31
Phoenix Contact 1714971 two position screw terminals $1.34 $1.31
Rf1 4.7 Ohm .25W resistor $0.37 $0.03
Rf2 4.7 Ohm .25W resistor $0.37 $0.03
RL1 220 Ohm .5W resistor $0.37 $0.03
Rs 4 mOhm 4W resistor Ohmite 14AFR004E $1.98 $1.23
Ra1 47k Ohm .25W Resistor $0.37 $0.03
Ra2 47k Ohm .25W Resistor $0.37 $0.03
S1,2 2 pos DIP switch $0.53 $0.49
U3 INA226 Current and voltage sensor $6.33 $3.38
Current Sensor PC Board $0.00 $4.00
Molex 50-57-9404 (mating connector for cable) $0.68 $0.37
Molex 50-57-9404 (mating connector for cable) $0.68 $0.37
Alpha Wire 1174c SL005 4cond 22ga $1.00 $1.00
Labor $225.00 $62.09
SUBTOTAL $241.84 $77.81
Temperature Sensor Board
Schematic Description Prototype Cost Production Cost
CN1 Molex70555-0038 Locking connector $0.97 $0.96
U2 TMP102 Temp sensor (I2C) $5.95 $1.69
Temperature Sensor PC Board $0.00 $2.00
Molex 50-57-9404 (mating connector for cable) $0.68 $0.37
Molex 50-57-9404 (mating connector for cable) $0.68 $0.37
Alpha Wire 1174c SL005 4cond 22ga $1.00 $1.00
Labor $75.00 $29.21
SUBTOTAL $84.28 $35.60
Completed Assembly as Specified
Board Prototype Cost Production Cost
Control Board $1,402.30 $167.85
Current Sensor Board $241.84 $77.81
Current Sensor Board $241.84 $77.81
Temperature Sensor Board $84.28 $35.60
TOTAL COST $1969.96 $359.07

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