Transducer และ Sensors

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Transducer และ Sensors

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  • 5 (Transducer) (Sensors)

    5.1 () 5.1 4 5.1

    5.1 ()

    (Primary Sensors)

    A / DMicrocomputer

    mV

    Input

    Output

    Primary Secondary

  • 5 2

    (Secondary Sensor) (Sensing) (Pressure Transducer) (Output) 5.1.1

    1. - (Active Sensors) - (Passive Sensors) 2. - (Variable Capacitance Transducer) - (Variable Inductance Transducer) - (Variable Resistance Transducer) 3. - - - - 4. - - (ON OFF) -

  • 5 5 3

    5. - (Input Transducer) - (Output Transducers) 6. - 5.1.2

    (Capacitive and Inductive)

    (Capacitive) 5.2 )

    C = dA

    ro (5.1) o = Permittivity = 8.85 pF / m r = Relative Permittivity ( 5.1) A = (m2) d = (m) (5.1) C d, A r

    1. 5.2 ) x d + x

    C = xdA

    ro + (5.2) 2. 5.2 ) x A = wx w =

    C = d)wxA(

    ro (5.3)

  • 5 4

    5.2

    5.1

    (Material) (Dielectric Constant : r) Vacuum 1.0 Air 1.0006 Teflon 2.0 Wax 2.25 Paper 2.5 Amber 2.65 Rubber 3.0 Oil 4.0 Mica 5.0 Ceramic (low) 6.0 Bakelite 7.0 Glass 7.5 Water 78.0 Ceramic (high) 8000.0

    d

    .) .)

    x

    dx

    xl

    21.)

    d A

    .)

    ary

    dt

    .) (Pressure) .)

    F1

    F2M

    B2dd - x

    d + xA

    hl

    ba

    .) .)

    (Glass substrate) (Tantalum)

    (Folymer)

    (Chromium layer)

  • 5 5 5

    3. 5.2 ) x 2 ( 2 > 1 ) A1 1 A2 2 C = d

    A1ro + d

    A2ro

    A1 = wx

    A2 = w (l x) w = ; l = C = ]x)([d

    w122

    o l (5.4) 4. 5.2 ) ( ) ( 1) P y r

    y = P)ra(Et

    )1(163 222

    3

    2 (5.5)

    a = t = E = Youngs Modulus = Poissons Ratio C C

    C = Pa

    Edt16)1( 4

    3

    2 (5.6) d () C = oa2/d P = 0 (Zero) 5. (Differential or Push pull) () 3 5.2 ) F1 F2 x

    AB C1 C2 MF1 MF2

    C1 = xdA

    ro + (5.7) C2 = xd

    Aro (5.8)

  • 5 6

    C1 C2 x C1 C2 (Deflection) x 6. (Capacitive Level Sensor) 5.2 ) h ( 0.1 mho/cm3) b a ( b > a) r 2or/loge(b/a)

    Ch = )a/b(log)h(2

    )a/b(logh2

    eo

    ero + l

    Ch = ]h)1([)a/b(log2

    reo + l (5.9)

    (Deflection Bridge) 5.3

    ) )

    5.3

    5.3 5.3 ) 5.1 ) Ch (5.9)

    Z1 = 1/(jCo) ; Z2 = R2 Z4 = 1/(jCh) ; Z3 = R3

    Z2

    Z3

    Vs

    I1I2CO

    Ch

    Vth

    R

    R

    Vs

    I1I2

    Vth

    L1

    L2

  • 5 5 7

    Vth = Vs

    +

    +23

    h0

    RR1

    1

    CC1

    1

    Vth = 0 hmin Co = Chmin(R3/R2)

    Vth = Vs

    +

    +23

    23

    hminh

    RR1

    1

    RR

    CC1

    1 (5.10)

    R3/R2 1 (5.10)

    Vth Vs

    1CC

    RR

    minhh

    32

    5.2 ) C1 = xdA

    ro + (5.7) C2 = xd

    Aro (5.8)

    Z1 = 1/(jC1) ; Z2 = R Z4 = 1/(jC2) ; Z3 = R Vth = Vs

    + 2

    1CC

    C21

    2 (5.11)

    Vth = xd2VS (5.12)

    Vth x (Pushpull) 7. (Capacitive Lumidity Sensor) 5.2 ) ()

  • 5 8

    0 100 % RH 0 % 375 pF 1.7 pF / %RH C = 375 + 1.7(RH) pF (5.12) (5.12) 2 % 1 % (Oscillator) 100 k 100 kHz Loss Tangent tan tan = CR

    1 (5.13) C = 500 pF tan 0.03 5.4) (Pure) (Q)

    Q = CRn = R LC

    5.4 RC R C C Q R fn

    105 Hz Q 30

    Vi = 0

    VF L

    RCH(s)

    G(s)+-

    VO

  • 5 5 9

    5.5

    (e.m.f.) e.m.f. = Current Resistance (5.14) 5.5 ) i n (Ferromagnetic Material) (m.m.f.)

    in

    in

    (air gap)

    R

    L

    d air gap

    2 rt

    )

    )

    2 a a + x

    a - xx

    L1

    L2

    )

    Central flux pathc r

  • 5 10

    m.m.f. = Flux Reluctance = (5.15) m.m.f. = ni

    = ni (5.16) 1 N n

    N = n = in2

    (5.17)

    L

    L = iN =

    2n (5.18) (5.18)

    = Arol (5.19)

    l = o = Permeability = 410-7 H/m r = Relative Permeability A = 5.5 ) (Air Gap) 1 5.5 ) (Variable Reluctance ) 3 (Armature) total = core + gap + armature (5.20) R r2 core = 2

    co rR

    = 2co r

    R (5.21)

  • 5 5 11

    2d 1

    gap = 2o r

    d2 (5.22)

    2R 5.5 ) 2rt

    armature = rt2R2ao = rt

    Rao (5.23)

    total = 2co r

    R + 2o r

    d2 + rt

    Rao (5.24)

    o =

    + t

    1r

    1r

    Raco

    = total = o + kd (5.25) k = 2

    o r2

    n = 500 R = 2 . r = 0.5 . t = 0.5 . c = a = 100 , o = 1.3 107 / H, k = 2 1010 /Hm L = 19 (mH) () L = 7.6 1 (5.18) (5.25)

    L = kdn

    o

    2

    + = d1L0+ (5.26)

    (5.18) (5.26) Lo = n2/ o = = k/ o

    (5.26) Lo L d 5.5 ) 2a (5.26) 5.5 ) - L1 L2

    L1 = )xa(1L0 + (5.27)

  • 5 12

    L2 = )xa(1L0 ++ (5.28)

    L1, L2 x 5.4 ) Z1 = jL1) ; Z2 = R Z4 = jL2) ; Z3 = R Vth = Vs

    + 2

    1LL

    L21

    1 (5.29)

    Vth = )a1(2xVS +

    (5.30)

    x Vth x (Pushpull) 0.5 Lo 25 mH 70 0.5 R 5.6

    5.6 LC R L

    Vi = 0

    VF

    L

    R

    C

    G(s)+-

    VO

    H(s)

  • 5 5 13

    LVDT (Linear Variable Differential Transformer)

    5.7 L.V.D.T.

    LED

    5.8 LED

    5.9 LED

    LED

    Vo sin(2pfSt +j )V1

    V2

    Phase-sensitivedemodulator

    + Low pass filterVDCtf2sinV SS

    primarysecondaries

    x = 0

    x = l

  • 5 14

    5.9 LED R2 LED LED TIL139 Taxas Instruments 5.10 LED

    5.10

    (Opto isolator)

    (LED) 5.11 5 12

    R1 270 W

    R2 10 kW

    LED 1Q1

    + 5V

    LED

    ) )

  • 5 5 15

    5.11

    1. (Inductive Sensors)

    5.12 (www.balluff.com/solutions/inductive.htm)

    5.12 5.13

    680 W 4.7 kW

    + 5V

    + 12V

  • 5 16

    1) () (Active Zone : Coil) 2) (Oscillator) 3) (Evaluator) 4) (Trigger) 5) (Status display)

    5.13

    6) (Internal Constant Voltage Supply) 7) (External Voltage) 8) (Output and Protective) 9) ( ON-OFF)

    5.13 1 2 3 4 5 8 ON OFF (Mild Steel) (Factor) = 1 = 0.35 = 0.25 10 3.5 2.5

    G1

    2 3 4 5

    6

    7

    89

  • 5 5 17

    (Specification)

    5.14

    5.14 5.14 - (Sensing Range) (ON) (OFF) - (Norminal Sensing Range : Sn) - (Real Sensing Range; Sr) 90 % 110 % (Sn) - (Useful Sensing Range : Su) EN 50010 81 %121 % - (Working Sensing Range : Sw) - (Sn) (Mild Steel) (Factor)

    0.81 Sn

    Sr

    S WS U

    1.21 SnSn

    0.9 Sn1.1 Sn

    d

  • 5 18

    (Eddy Current) - (Repeatability) EURO-NORM - (Switching Hysteresis) (ON) (OFF) 2. (Capacitive Sensor)

    5.15

    (www.balluff.com/solutions/inductive.htm)

    1. Active Electrode 2. 3. Earth Electrode 4. 5.

    5.16

    123

    4

    5

  • 5 5 19

    Active Earth Electrode

    5.16 (Dielectric Constant) () (ON) (OFF) 2

    5.2

    ()

    1.0 1.0

    0.3 ... 0.5 0.3 ... 0.6 0.3 ... 0.5 0.2 ... 0.7 0.1 ... 0.3

    (Potentiometer)

  • 5 20

    5.17 (www.ifmefector.com/ifmus/web/capacitive.htm)

    17 5.2

    5.2.1. ( 4 ) 3 1) VS 2) R4

    3) 23

    RR

    1) (Range) (Output)

  • 5 5 21

    2) (Linearity)

    3) (Sensor)

    IMIN = IMAX = RIMIN = RIMAX =

    VMIN VMAX

    VMIN =

    +

    +23

    IMIN4S

    RR1

    1

    RR1

    1V (5.31)

    VMAX =

    +

    +23

    IMAX4S

    RR1

    1

    RR1

    1V (5.32)

    VMIN = 0 I = IMIN (5.31) (5.32)

    IMIN

    4R

    R =

    23

    RR

    (5.33)

    3 1) (Sensor) (Self Heating) PD = i2RI

    PD 24I

    I2S )RR(

    RV + (5.34) PD = i = ( i2) 2) (Linearity) Eth () VMIN = 0 V I

    VIDEAL MINMINMAXMAX

    MINMAXMAX III

    VIIIV

    (5.34)

  • 5 22

    N(I) = Eth VIDEAL (5.35) ( N )

    N 100VVE

    MAXIDEALth (5.36)

    R3/R2 (5.31)

    (5.32) R4 = IMIN23 RR

    R (5.37)

    Sth

    VE

    =

    23

    IIMIN

    23

    RR1

    1

    RR

    RR1

    1

    +

    + (5.37)

    Sth

    VE

    = v , r = 23

    RR

    x = IMIN

    IR

    R (5.37)

    v = r11

    xr1

    1+

    +

    v = r11

    rxx

    ++ (5.38) v x 5.18 x 0.1 2.0 r = 0.1, 1.0 , 10.0 100

    5.18 (v = r11

    rxx

    ++ )

  • 5 5 23

    v = 0 x = 1 I = IMIN v(x) r 5.1 0-10 (Bar) 120 120 3 (Output) (Input) (Infinite) 30 (mA) 1) 2) 338 / ( 1) 10 1) R1 = R2 = R3 = 120

    I1 ADC

    Vi = I1(Ru + R3)

    Ru = 120 I1 0.03

    Vi = 0.03 (120 + 120 ) = 7.2 V 7.2 2) 10 = (338 m/bar ) (10 bar) = 3.38 Ru = 120 + 3.38 = 123.38

    VO =

    ++ 21

    13u

    ui RR

    RRR

    RV

    5.2 100 50 60 0 2 1 (Sensor Transducer) 100 High

  • 5 24

    5.19 RTD 30 R 65 150 65 0.004 / 1 30 / 50, 80 100 R(t) = Rt0(1 + 0 T) ... 50 C = 150[1 + 0.004 (50 65 )] = 141 ... 80 C = 150[1 + 0.004 (80 65 )] = 159 ... 100 C = 150[1 + 0.004 (100 65 )] = 171 1 RTD

    T = DPP

    T = ( Self Heating) P = RTD PD = RTD (W/1C) P = PD T = (30 mW/C) (1C)

    100OC

    Temperaturetransducer

    heater

  • 5 5 25

    = 30 mW ( 80 C )

    I = RP =

    159mW30

    = 13.7 mA RTD 50 C 5.0 RTD R4 R2 13.7 mA RTD 80 C V = IR = (13.7 mA)( 159 ) = 2.17 V R2

    R2 = mA7.13)17.25(

    = 206.5 R2 = 220 50 C R1 = 220 R3 141

    5.20 5.1

  • 5 26

    50 C V = 1412201415141220

    1415 ++ = 0 () 80 C V = 141220

    14151592201595 ++ = 0.1447

    100 C V = 1412201415171220

    1715 ++ = 0.2338 5 Vref = 13.8 (0.2338) = 3.23

    5.21

    () 5.3

    (ADC) (DAC) ADC

  • 5 5 27

    ADC () ADC ADC (Accuracy and Resolution)

    1 100 99 101 100 100 mV (0.1 volt) 10.6 10.65 ( 50 mV) 10.1 10.2 10.5 1 1 10 9.2 9.8 0.1 9.2 9.8 (Conversion Time)

    (AD) ( (Counter Stage)) 5.22

  • 5 28

    5.22 5.3 1.024 MHz 10 ? = T 2n T = n = = (1/1.024 106)(1024) = 1000 s = 1 ms 1 1 1 1,000 ( 5.22) (Gray Code Encoder) R2R 2 R2R R2R R2R 10 1000 () 10 / (1000 ) = 0.01 /

    DC

  • 5 5 29

    5.23 R-2R

    10,000 0.001 1 5.4 8 R 2R = 28 = 256 1 256 = (1/ 250) 100 % ( 1 / 256) = 0.4 % 5.5 8 R2R 10 ? 5.4 = 0.4 % 100 % 10 = 0.4 % (10 ) = (0.4 / 100) (10) = 0.04 V = 40 mV

    ( 0)

    ()

    R-2R

  • 5 30

    5.6 10 kHz 8 ? = 28 = 256

    / = 1 /(10 103) = 100 s = 100 s 256 = 25,600 s = 25.6 ms (Per Conversion) 5.7 8 10 kHz ? 10 kHz 25.6 ms ( 5.5) 1 = 1 / (25.6 10-3) = 1000 / 25.6 40 5.24 (ADC) (DAC)

    5.24

    R2R (Summing Opamp) R2R 5.3.1 (DAC)

    n BCD R2R 5.25

    ADC

    DAC

  • 5 5 31

    5.25 R2R R2R

    R2R 5.25 R 2R 1 k 2 k R2R +16 0 ( 1 0) R2R

    5.26 R2R 1,000 5.26 0 () 0 0 0 0 0 0 +16 1 23 = 8 +16 0 5.26 ) 8 ( 5.26 ), ) )) 5.26 5.26 ) 1 .. 2R R 5.26 ) R R 2R 2R 2 5.26 ) 2

    R R R R

    R

    R

    R

    R

    R

    R

    R

    R

    R

    R

    23 22 21 20

    +16 V

    1R

    23 22 21 20

    R R R

    2R2R2R2R

    ()

    +16 V

    R

    R

    23 22 21

    R R R

    2R2R2R2R

    234 4 3 2

    +16 V

    R

    23 22 21 20

    R R 2R

    2R2R2R

    4 3 2

    1

    +16 V

    23

    R

    2R2R

    4

    2221 20

    ()

    () ()

  • 5 32

    ... 2R 2R .. R 3 2 2R 2R 3 R ... R 4 3 2R 5.26 ) 5.26 ) ) 1 2 3 4 2R 4 +16 2R 2R 8 8 16 ( 24) 8 /16 16 8 0100 5.27 ) 2R 5.27 ) 3 +8 ... R 5.27 ) R 4 3 5.27 ) 4 +4 4 0100 4 16 (4/16 = 1/4) 0010 2 0001 1

    5.27 R2R 0100 1 (Superposition) 5.3

    +16 V

    1R

    23 22 21 20

    R R R

    2R2R2R2R

    ()

    R

    2322

    R R

    R2R2R2R

    234 4 3 2

    +8 V

    R

    23 22

    R

    R2R

    4 3

    23

    R

    2R2R

    4

    22+8 V

    +8 V

    ()

    () ()

  • 5 5 33

    5.3 ( 16 )

    (Volts) (Volts) 0000 0 1000 8 0001 1 1001 9 0010 2 1010 10 0011 3 1011 11 0100 4 1100 12 0101 5 1101 13 0110 6 1110 14 0111 7 1111 15

    20/() 2 1/2 10 20 / 210 1 / 1024 29 / 210 512 / 1024 = 1 / 2 10.24 1 00 0000 0001 (1 / 1024) 10.24 = 10 10 0000 0000 (512 / 1024) 10.24 = 5.12 10 0000 0001 5.12 + 0.010 5.13 5.8 5 +6.4 1 0 0 ) 1 0 0 0 0 ) 0 0 0 0 1 ) 0 1 0 0 0 ) 0 1 1 0 1 ) 1 0 0 1 0 ) 25 = 32 ; 1 0 0 0 0 = 16 1 0 0 0 0 = (16/32) (6.4) = 3.2 ) 0 0 0 0 1 = 1 0 0 0 0 1 = (1 / 32) (6.4) = 0.2 ) 0 1 0 0 0 = 8 0 1 0 0 0 = (1 / 4) (6.4) = 1.6

    ) 0 1 1 0 1 4.6321

    320

    324

    328

    320

    ++++ = (13 / 32) (6.4) = 2.6

    ) 0 1 1 0 1 4.6320

    322

    320

    320

    3216

    ++++ = (18 / 32) (6.4) = 3.6

  • 5 34

    R -+ VO

    LSB

    R

    2R2R2R

    R

    2R

    2R

    MSB

    Vref

    R-2R

    5.9 8 51.2 ) 1 0 1 1 0 1 0 0 ) 1 0 0 1 1 1 0 1 ) 0 0 0 1 1 1 0 0

    ) (Vout) = 82457

    22222 +++ (51.2)

    = 25641632128 +++ (51.2) = 36

    ) (Vout) = 802347

    222222 ++++ (51.2)

    = 25614816128 ++++ = 31.4

    ) (Vout) = 8234

    2222 ++ (51.2)

    = 2564816 ++ (51.2) = 5.6

    R 2R

    R-2R 5.28

    5.28 R 2R

    0 0 1 Vref

  • 5 5 35

    (Unibipolar) 5.28 (Sign Bit) 5.28 10

    = 000977.0024,11

    21

    21

    10n === (Part Per Million (ppm)) 0.000977 100 % = 0.0977 % 0.000977 1,000,000 ppm = 977 ppm 5.4

    5.4

    (Resolution) (n)

    % ppm 4 6.2500 62,500 8 0.3906 3,906

    10 0.0977 977 12 0.0244 244 14 0.0061 61 16 0.0015 15 18 0.0004 4

    8 0.5 16 15 ppm BCD (BCD Resolution)

    BCD

  • 5 36

    5.10 BCD 8 () ? = ppm000,10%1100

    1 == 5.11 BCD 12 BCD 12 4 3

    = %1.0%10010001

    10001 ==

    = ppm000,000,110001 =

    5.4 12 244 ppm BCD 12 1,000 ppm (Weighted Resistance DAC) 5.29 5.5

    5.29

    100 k200 k400 k800 k

    100 k

    -+

    VO

    D3D2

    D1D0

    ( 0 + 5 )

  • 5 5 37

    5.5 4 (+5 V = 1 , 0 V = 0 , )

    D3 D2 D1 D0 V0(Volts) 0 0 0 0 0.000 0 0 0 5 0.625 0 0 5 0 1.250 0 0 5 5 1.875 0 5 0 0 2.500 0 5 0 5 3.125 0 5 5 0 3.750 0 5 5 5 4.375 5 0 0 0 5.000 5 0 0 5 5.625 5 0 5 0 6.250 5 0 5 5 6.875 5 5 0 0 7.500 5 5 0 5 8.125 5 5 5 0 8.750 5 5 5 5 9.375

    5.29 (0 5 ) +5 D0

    )V5(k800k100 +

    = 0.625 V

    D3 +5

    )V5(k100k100 +

    = 5 V

    5.5 5 = 1 0 = 0 5.30 ... R 2n-1R

  • 5 38

    5.30

    5.3.2 (ADC)

    R2R R2R R2R ADC (Digital Ramp (Staircase) ADC)

    R2R 5.31 1. ( BCD) ( 0 ) 2. () 3. ( 5.31 ))

    R

    -+

    VO

    (Vref)

    R

    2R

    4R

    2n-1R

    ()

  • 5 5 39

    5.31 ADC ) )

    5.12 ADC 8 2 MHz 28 256 2 MHz

    T = 1/f = 1/(2 106) = 0.5 s T N = 0.5 s 256 = 128 s ADC

    = 1/2n 100 % n = () 5.13 ADC 12 = 1/212 100 % = 0.0244 % = 244 ppm ADC ADC 1

    -

    +

    )

    )

  • 5 40

    = .fsn V121

    Vfs = ADC n = 5.14 ADC 12 10.24 ? = .fsn V12

    1

    = mV5.2)V24.10(12

    112 =

    ADC 2n 1/f n = () f =

    = f/122f/12 1nn =

    5.15 ADC 10 2.5 MHz ?

    = f/122f/12 1nn =

    = S8.204105.2

    12 69 =

    (Successive Approximation Converter)

  • 5 5 41

    (Vi)

    LSB

    (SAR)

    MSB

    DAC

    -+

    5.32

    5.33

    Vi MSB (0) 1

    1 Vi DAC 5.34 )

  • 5 42

    5.13 ) ) SAR 3 011 3.4 V ( 8.0 V)

    ) 3.4 V ( 8.0 V) ADC0804

    ADC0804 ADC0804 ( Stand-alone operation) 5.35

  • 5 5 43

    5.35 ADC0804 Stand-alone Vcc = +5 Vdc R C

    f )RC1.1(1 (5.39)

    5.38 9 Vref

    Vref = 2Vcc 6 7

    7 0.0 5 ADC 0804 IC CPU 8080A 8080A 8228 Clock 8224 8048 MPU (Microprocessor Unit) WR , INTR , CS RD WR INTR (Pushbutton) 100 (s) 8 11 18 11 MSB 0.0 0000 0000 (00H) 1111 1111 (FFH) +5.0

    1112131415161718

    3521

    194

    6

    7

    9

    20

    10 8

    R10 k

    C 150 pF

    +Vcc

    MSB

    LSB

    Vi(+)

    Vi(-)

    Vcc/2

    ADC0804

    WRINTR

    CS

    RD

    CLK R

    CLK INDigitalOutput

    Analoginput

    Start

  • 5 44

    1 LSB +5.0 28 = 256 1 ( LSB) 256

    V0.5 = 19.53

    5.16 5.35 ADC0804 1 LSB 1) 2.5 2) 0010 0010 (22H) 1) 2.5 1000 0000 1 bit 27 = 128 128 19.53 mV = 2.5 V 2) ( 25 + 21 ) 19.53 mV = (32 + 2) 19.53 mV = 0.664 V (Span Adjust)

    ADC0804 0.0 5.0 0.0 2.0 2.0 5.0 Vref 9

    (Span) Vref = 2.0 V / 2 = 1.0 Vdc

    Vref = 2 = 2

    (5.40)

    5.36 Vref (5.41)

    Vref = RRR2RR

    V21

    2CC ++

    + (5.41)

    (5.41) 5.36

    Vref = +5 Vdc +++

    k5.0k7.4k1k25.0k1 = 1.01 Vdc

    Vref =1.0 Vdc 0.0 2.0 2.0 1111

    1111 (FFH) LSB 256V0.2 7.8

  • 5 5 45

    5.36 Vref ADC0804

    (Offset Zero Shift)

    ADC0804 +1.5 +4.0 6 7 2.5 (4.0 1.5 ) (5.40)

    Vref = 2 = 2

    V5.2 = 1.25 Vdc

    Vref 9 7 (Lower Limit) (Offset)

    OFFSET Vi- = (5.42)

    Vref = 1.25 Vdc Vi- = 1.5 Vdc 1.5 0000 0000 4.0 1111 1111

    LSB 256V5.2 9.77

    (Positive and Negative Input Voltages)

    5.37 5 +5 (R R) 6 7

    1112131415161718

    3521

    194

    6

    7

    9

    20

    10 8

    R10 k

    C 150 pF

    MSB

    LSB

    Vi(+)

    Vi(-)

    Vcc/2

    ADC0804

    WRINTR

    CS

    RD

    CLK R

    CLK INDigitalOutput

    Analoginput

    Start

    +Vcc = + 5 Vdc

    R1 4.7 k

    +Vcc = + 5 Vdc

    R 500 k

    R2 1 k

  • 5 46

    5.37 1. Vi = -5 Vi+ = 0.0 0000 0000 (00H)

    2. Vi = 0.0 Vi+ = 2.5 1000 0000 (80H) 3. Vi = +5.0 Vi+ = +5.0 1111 1111 (FFH) Vi+ 5.0 Vi+ 0.0 + 5.0 Vi MSB 0 (

    0.0) Vi 0 MSB 1 ( 0.0) LSB 10 V/256 = 39.01

    (Testing)

    ADC0804 A/D

    1112131415161718

    3521

    194

    6

    7

    9

    20

    10 8

    R10 k

    C 150 pF

    MSB

    LSB

    Vi(+)

    Vi(-)

    Vcc/2

    ADC0804

    WRINTR

    CSRD

    CLK R

    CLK INDigitalOutput

    Start

    +Vcc = + 5 Vdc

    +Vcc = + 5 Vdc

    Vref

    RR

    +Vi-

  • 5 5 47

    5.38 LED VCC = 5.120 Vref VCC / 2 = 2.560 LSB 5.120 V /256 = 20

    5.38 LED 1. 1010 1010 (AAH) (128 + 32 + 8 + 2) (20 mV) = 3.400 2. 0101 0101 (55 H) (64 + 16 + 4 +1)(20 mV) = 1.700 LED A/D 1 (high) LED

    0 (Low) LED

    LED low 0 =

    1112131415161718

    3521

    194

    6

    7

    9

    20

    10 8

    R10 k

    C 150 pF

    + 5 Vdc

    LSB

    Vi(+)

    Vi(-)

    VCC/2 = +2.560 Vdc

    ADC0804

    WRINTR

    CSRD

    CLK R

    CLK INDigitalOutput

    Start

    +VCC = + 5.120 Vdc

    Vref

    R =1.5 kMSB

  • 5 48

    LED high 1 = 1011 0010 5.39 MSB LSB

    5.39

    (Shaft Position Conversion)

    360 () 5.38 3 8 360 8 360 / 8 = 45 10 15 360 /215 360 / 32768 ~ 1 /60 ( ) 5.17 10 ? = 360 / 210 = 360/1024 = 0.36 1/3 0 0 0 0 0 1 20

    0 0 0 21 22 0 0 1 3 16 ( 1 ) 1 1 1 1 0 0 0 20 21 1 1 1 22 000 011

  • 5 5 49

    1 ( 180 ) 180 1 1 (Code Disk) Gay tobinary 1

    Decimal Gray Code Binary Code Decimal Gray Code Binary Code 0 0000 0000 8 1100 1000 1 0001 0001 9 1101 1001 2 0011 0010 10 1111 1010 3 0010 0011 11 1110 1011 4 0110 0100 12 1010 1100 5 0111 0101 13 1011 1101 6 0101 0110 14 1001 1110 7 0100 0111 15 1000 1111