Matakuliah
Tahun
Versi
: H0262/Pengukuran dan Instrumentasi
: 2005
: 00/01
Pertemuan 6
Signal conditioning
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Mahasiswa dapat menjelaskan signal
conditioning
2
Outline Materi
•
•
•
•
Materi 1 : Metode jembatan
Materi 2 : Design reactive bridge
Materi 3 : Instrumen amplifier
Materi 4 : Milivolt converter
3
Signal Conditioning
• Metode Jembatan .
Gb 6.1 Jembatan AC.
0
0
ETH = VS
(
Z1
-
Z1+ Z4
ZTH =
Z2Z3
Z2 + Z3
Z2
)
Z2+ Z3
Z1Z4
+
Z1+ Z4
0
Tegangan output jembatan :
ETH = VS (
R1
R1+ R4
-
R2
)
R2+ R3
Tegangan output single elemen jembatan strain gauge :
ETH = ¼ VS Ge .
v(x) =
X-1
2 ( x+1 )
 ¼ (x-1)
6
0
Output voltage two elemen jembatan resistance thermometer.
Gb 6.2 Termometer bridge
7
0
ETH = VS
R0
R3  (T1 – T2)
Gb 6.3 kondisi dan karakteristik jembatan termistor .
8
0
1
Titik O  0= VS (
1
-
1+ R4 /R298
Titik Q  0,5 = VS (
1+R3/R2
1
1+ R4/R323
)
1
)
1+R3/R2
9
Design reactive bridge .
Gb 6.4 Reactive bridge .
0
10
0
Eth = VS (
1
1
1+ CminR3/ CR2
)
1+R3/R2
Tegangan output capacitance pushpull bridge
ETH= Vs x / 2d .
11
Tegangan output inductive pushpull bridge:
ETH =
0
Vs
X
2(1+ a)
Amplifier.
• inverting amplifier
•Non inverting amplifier
•Differential amplifier
•Integrator amplifier
•Summing amplifier
12
0
Instrument Amplifier.
Gb 6.5 Penguat Instrumentasi
13
0
Vout = K ( V2 – V1 )
Aol
CMRR = A
CM
Osilator.
Gb 6.6 prinsip osilator .
14
0
| G(jw) |•| H(jw) | = 1 .
arg G(jw) + arg H(jw) = -180º .
15
• Milivolt converter .
Gb 6.7 milivolt converter
0
16
0
I = 1/ RS [ E T1,0 + VS ]
Inspeksi gambar milivolt converter lebih akurat
memberikan hasil persamaan arus :
I=
K
1+KRS
[ ET1,0 + VS]
dimana KRS  1.
17
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