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Example of User to System Level – Flowdown

Definition: “ Statements of desired product performances and features used to define and quantify a product design” User Level : Special list or labels which state the intended application and/or purpose of the product (Labeling)

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Example of User to System Level – Flowdown

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  1. Definition: “Statements of desired product performances and features used to define and quantify a product design” • User Level: Special list or labels which state the intended application and/or purpose of the product (Labeling) • Product Level: (System Level) Quantitatively state all features, performances, and interfaces in “Eng Terms” • Block Level: State all features, performances and interfaces describing the block in “Engineering Terms” • User Level >>> Validation (End User Testing) • Product & Block Level>>>Verification (Bench Testing) Efficient Engineering teams fully specify before they design !!

  2. Example of User to System Level – Flowdown User Level: “Indoor/Outdoor Operation & Storage” Product or System Level: Max Oper Temp Range: -40C to 55C Max Oper Humidity Range: 0-100% Non condensing Max Oper Altitude Range: -300ft to 15,000 ft above sea level Max Storage Temp Range: -50C to 65C Max Storage Humidity Range: 0-100% Non condensing Max Storage Pressure Range: 0.5 to 1.5ATM

  3. Requirements Imply Proof of Satisfaction !Implied Product Design Integrity ! • Many Gov’t Agencies mandate that ALL product requirements should be user validated and/or engineering verified (tested or justified). A requirement which cannot be verified or validated should not be stated unless objective evidence can be compiled to prove its satisfaction • Requirement Categorization Used in this Course: • Standard: Common to ALL Project Teams • Performance: Unique to Project and Technology, For Differentiating

  4. Design Blocks • Complex products require that the design be broken into logical design elements (termed blocks in this course) • Blocks form the basis of standardized design elements in this course. • The terms Product and System are used interchangably • Product Level Requirements can either be allocated or just associated to all design blocks. • The Project System Design entails defining ALL Block Performance Reqs incl Interfaces and Functions

  5. Design BlocksLogical Design Partition Elements Mandatory Rules About Design Blocks: • Design Blocks Must Cover 100% of Product Assembly • All Design Blocks Must have an Assigned Team Member (Owner) • Min 1 Design Block is Assigned to Each Team Member • Design Blocks May NOT be Jointly Assigned/Owned • Team Members May be Assigned More Than 1 Design Block • Min of 5 Elec Components Must be formally Specified by each Team Member and May Spread Across more than 1 Design Block This includes all R’s, C’s, L’s, Sockets, Connectors, Cables, Displays, Relays, Switches, etc Blocks form the basis of standardized design elements that are evaluated in this course

  6. Allocation and Associationto Design Blocks • ALLProduct Level Requirements Must be allocated or associated to each Design Block within the project to complete a System Design Phase • Allocated: % of total budgeted to applicable design blocks plus margin. For example: Product Cost, Power Consumption, Mass …. • Associated: Used when allocation is not applicable. For example: Country(s) of Market, Annual Volume, Safety Standards ….

  7. Product Level - Standard Requirements • Standard Requirements are those requirements which are universal and can be applied to nearly all products and hence final projects • Standard Requirements may or may not be differentiating depending upon project goals but MUST be part of the minimum description of the product Standard Reqs Are Common to Nearly ALL Projects

  8. System - Std Reqs: Market & Business Case Choose & Understand your Market “before” …………. you design a product RequirementUnits to Specify • Company Name(s), Model#(s) • Total $/Region, Info Source • $/unit as sold to customers • List of Countries or Regions • Min/Max Age, Sex, Restrictions • Ind, Auto, Home, Wearable, etc • $/unit in volume production • $/unit in volume production • # of units/yr • Competitors • Market Size • Average List Price • Market Geography • Market Demography • Intended Application • Material Cost • Manufacturing Cost • Annual Volume

  9. System - Std Reqs: Env & Safety Consider Simultaneous Min or Max CasesSome will NOT be “testable” RequirementUnits to Specify • CoRange • Rh% Range • Meters or ATM, Range • CoRange • Rh% Range • Meters or ATM, Range • Time in Days or Years • List of IEC or FCC stds • List UL, IEC or other stds • Min Oper Temp Range • Min Oper Humidity Range • Min Oper Alt or Press Range • Min Storage Temp Range • Min Storage Humidity Range • Min Storage Alt or Press Range • Max Storage Duration • Primary EMC Standards • Primary Safety Standards

  10. System - Std Reqs: Power Input(s) Must consider power source(s) early Undefined DC power sources NOT allowed RequirementUnits to Specify • AC, Battery, Photovoltaic, Generator, Fuel Cell, Thermopile etc • Permanent or Temporary • Voltage Range, For each Source • Max Total Watts, For each Source • Watt-Hours/Yr for AC Power, mAHrs for Batteries (Calendar Life Time) • Energy Source List • Source Connection List • Min Oper Voltage Range • Max Power Consumption • Max Energy Consumption

  11. System - Std Reqs: Mechanical Package and Mechanical Design Impact Many Product Aspects RequirementUnits to Specify • Cm3 Total for Entire Product • Cm Max LxWxH for 1 unit • Kilograms • Type & Style (subD, BNC, etc) • Total # • Cm2 Total • G force (Grms), # Reps (depends on environment) • Max Volume • Max Ship Container Size • Max Mass • Elec I/F Connector(s) • Max # of PC Bds • Max PCB Circuit Area • Max Shock

  12. System - Std Reqs: Mfg & Life Cycle Product designs should consider full “life cycle” from Mfg process to Disposal RequirementUnits to Specify • # Total Parts incl elec & mech • # of Unique Parts • $ (Parts+Mfg=Product Cost) • $ (Parts+Mfg=Product Cost) • Time = MTBF(yrs) • Time (yrs) • Return, Recycle, Dispose, etc • Time (yrs) • Dispose or Repair, Factory or Field • Max Parts Count • Max Unique Parts Count • Parts/Mat $ Allocation • Asm/Test $ Allocation • Product Life, Reliability • Full Warranty Period • Product Disposition • Production Life Support • Service Strategy

  13. System -Performance Requirements • Performance Requirements are those requirements which are specific to a product and project • Performance Requirements differentiate the product from all other similar products • Performance Requirements should describe …. • Signal Interfaces • Mechanical Interfaces • Features, Options • Modes of Operation • Performance Parameters • User Controls • User Displays and Outputs

  14. System Perf Reqs: Functions & Capabilities Example RequirementDefinition • Accuracy, Resolution, Frequency of Update, Range • Inputs & Output Capability • Ex. RF: Distance, Sensitivity • Ex. Serial Link: Speed • Speed, Accel, Torque, Directions, Cycles, etc. • Examples: • Laser Sight Alignment • SSB & BFO Operation • 650Mbyte Capacity • Gauge, Measurement of Some Physical Quantity • Basic Elec Capabilities • Basic Mech Capabilities • Basic Functions/Capabilities

  15. System – Perf Reqs: Modes of Operation(Must be Considered if Applicable) Others May Apply RequirementDefinition • ON/OFF, ON/AC, ON/Battery, etc • Standby, Idle, etc • Program, Configure, etc • Diagnostic, Test, etc • Power Modes • Power Saving Modes • Calibration Modes • Service Modes

  16. System – Perf Reqs: Power Input(s)(Must be Considered if Applicable) All Applicable Must Be Defined RequirementDefinition • Hz, Range • EFT, Surge, Dropout, etc • Pb-Acid, Li, NMh, Alk, etc • CR2032, C, D, AA, etc • Min mA-Hrs • AC Power Freq Range(s) • AC Power EMC Stds • Battery Chemistry • Battery Std Size • Battery Capacity

  17. System – Perf Reqs: Electrical Functions(Must be Defined if Applicable) There may be others to Add RequirementDefinition • Voltage or Current Gain Ranges • Input – Output SNR • Frequency Response • Linearity and THD • Delay in uSec or mSec • Computation or Algorithm • Compute Speeds in Ops/Sec • Input – Output Delay • Analog Functions • Digital Functions

  18. System – Perf Reqs: Electrical Interfaces(For each signal “grouping”) Every Signal Needs to be Defined in Detail Electrical Signal ReqDefinition • Analog, Digital, or Power • Input, Output, Bidirectional • RS170 Video, RS232, USB, Custom, etc • Voltage Range, Frequency or Bandwidth Range • Impedance or Current Range • Offset Voltages, Currents • Error Voltages, Currents • Max Noise • Other Analog Characteristics • Signal Type • Signal Direction • Standard Definition • Basic Analog Characteristics • Detailed Analog Characteristics

  19. System – Perf Reqs: Electrical Interfaces(For each signal “grouping”) CANNOT use “TTL” or “CMOS” as Definition Electrical Signal ReqDefinition • Std, Schmitt Trigger • Std, TriState, Open Collector • Outputs: Voh, Vol, Ioh, Iol • Inputs: Vih, Vil, Iih, Iil, Vth • Bidirect: Both • Hi Z Leakage Currents • Min Transition Times • Min Setup & Hold Times • Max Frequency • Offset Voltages, Currents • Error Voltages, Currents • Max Noise • Other Analog Characteristics • Digital Input Type • Digital Output Type • Basic Digital Characteristics • Detailed Digital Characteristics

  20. System – Perf Reqs: Operator I/F Outputs(Must be Considered if Applicable) All Applicable Must Be Defined RequirementDefinition • Type, Size, Visibility, Speed, Color, Lumens • 7 Segment, Matrix, LCD • Total Char/Row, Total Rows • Total Size HxW • Daylight LCD, BLLCD, LED, EL, etc • CRT, TFT Panel, • 768, 1024, 1280, etc • 512, 768, 1024, etc • Volume, Pitch, Duration, Vibration, Flags, Other • Optical Indicators, Lights • Display Type • Display Char Matrix • Display Size • Display Illumination • Screen Type • Screen Min X Resolution • Screen Min Y Resolution • Mechanical Indicators

  21. System – Perf Reqs: Operator I/F Inputs(Must be Considered if Applicable) All Applicable Must Be Defined RequirementDefinition • Toggle, Slide, Mom Push, DIP, etc • Matrix or Ind Key Switches • Total Columns, Total Rows • Total Size HxW • Layout, Functions, Labels • QWERTY, QWERTY w/Keypad • USB, IBM 5 Pin, RS232, etc • Number of Keys • Range of Input • Number of Turns • Switch Type • Keypad Type • Keypad Matrix • Keypad Size • Key Definitions • Keyboard Type • Keyboard I/F • Keyboard Total keys • Analog Dials

  22. System – Perf Reqs: Mech Interfaces(Must be Considered if Applicable) Others May Apply RequirementDefinition • Feet, Brackets, Clamps, etc • None, Grips, Bars, etc • Temp, Pressure, Humidity, RPM, Acceleration, Dist, etc • Sub D, IEC-320, USB, etc • Mounting • Carry Handles • Sensory • Connectors

  23. Compare Your Possible Projects Project Recommendation Reqs Down Select Your Project Ideas: • Interest: • Does the project hold interest for ALL team members? • Can you identify similar products in the market? • How unique is the project compared to previous capstone projects? • Block Diagram: • Do the project blocks best match the skills and resources available on the team? • Does the block diagram contain at least 1 robust design block for each team member? • Is the block diagram overly complex 3 Possible Proj Brain Storm Ideas

  24. Compare Your Possible Projects Project Recommendation Reqs Down Select Your Project Ideas: • System Perf Requirements: • Can you list the key differentiating performance requirements which would create market demand? • Are you able to quantify the key system performance requirements? • System Std Requirements: • Can you quantify ALL the system standard requirements? • Can you allocate applicable system standard requirements to ALL blocks? 3 Possible Proj Brain Storm Ideas

  25. Compare Your Possible Projects Project Recommendation Reqs Down Select Your Project Ideas: • Prototype and Resources: • How difficult will it be to construct a prototype to demonstrate the primary functionality and performances? • Is the project dependent upon any development tools which may be difficult to procure or gain access to utilize? • Does the prototype depend on key components with lead times that could exceed the project timing requirements such as sensors, displays and transducers? • Does the available financial resource match the estimated cost of the prototype? 3 Possible Proj Brain Storm Ideas

  26. Excel Requirement Flowdown Template • Project Requirements Management Tool • Prerequisites For Use: • Team is assigned, Project is Selected by Team Decision • Product Block diagram is finalized (# of blocks, ownership, interfaces, etc) • Most Product Level Requirements have been proposed, discussed, agreed to • Spreadsheet Supports up to 10 Total Blocks (can be modified for more) • Data Is Entered In the Std and Perf Req sheets (1st two sheets) ONLY • Data Is Entered into Beige Shaded Blocks Only ! • DO NOT enter data into the Block Spreadsheets • Block”n” sheets Xfer ALL info, titles, etc from Std and Perf Req sheets • Linkages are Built In for Block levels down to the Block-Block section

  27. Excel Requirement Flowdown Template Each Team Should Customize Template as Needed • Number of Design Blocks • Hide Columns if Unused, Fewer Blocks • Delete Extra Block Sheets • Be careful NOT to break Block linkages back to Standard and Perf Reqs Sheets • Add specific-unique Block Requirements in the Block-Block sections (next lab)

  28. Excel Requirement Flowdown Template: Product Level - Standard Categories: Market, Power, Mechanical, Environmental, Safety, Manufacturing, & Life Cycle

  29. Excel Requirement Flowdown Template: Product Level - Standard Quantified Requirements, Min, Max Enter Number in Beige Shaded cells Green Cells Autocalculate

  30. Excel Requirement Flowdown Template: Product Level - Standard Unquantifiable Requirements May also have Suggested Lists Enter (Text) Countries, Names, Types, Styles, Stds, etc in Beige shaded cells

  31. Excel Requirement Flowdown Template: Product Level - Standard For Allocations: Enter #% for each block Total % Allocated in listed at right 1 Block May be Assigned as “Margin” and allocated a reasonable % of total OR … Total % Used May be less than 100%

  32. Excel Requirement Flowdown Template: Product Level - Standard For Associations: Enter “XX” for each block that is associated with the product level requirements The XX will transfer to each block sheet.

  33. Excel Requirement Flowdown Template: Product Level - Performance Categories: • User Inputs • User Indicators & Displays • Operation Modes • Electrical Interfaces • Electrical Performances • Mechanical Interfaces • Safety Caution: Perf Requirements Listed May NOT be applicable to your project Use only those necessary Add additional as necessary but be careful not to break links

  34. Excel Requirement Flowdown Template: Product Level - Performance Most Requirements are Quantifiable: Min, Max Must be Entered as Defined Enter Numbers in Beige Shaded cells

  35. Excel Requirement Flowdown Template: Product Level - Performance Unquantifiable Requirements have Suggested Lists Enter (Text) in Beige shaded cells

  36. Excel Requirement Flowdown Template: Product Level - Performance Same Scheme for Allocation and Association Caution: Not ALL quantifiable requirements will allocate, you may need to fall back on just association

  37. Excel Requirement Flowdown Template: Product Level - Performance • Product Level Electrical and Mechanical Interfaces shown here will transfer to blocks to which they are contained in. (but they must be associated correctly)

  38. Excel Requirement Flowdown Template Example of Block Output from Tool

  39. Block-Block Interfaces: Must be customized to each block Categories: • Digital Signal Inputs • Digital Signal Outputs • Analog Signal Inputs • Analog Signal Outputs • Power Inputs • Power Outputs • Electrical Transfer Functions • Mechanical (Connectors) Caution: Block Unique: Requirements Listed May NOT be applicable to your project Use only those necessary Add additional as necessary but be careful not to break links

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