2. 2
A. Static conditions 0
,
0
dt
dy
dt
dx
B. Dynamic conditions )
(
))
(
(
0
t
x
dt
t
y
d
a
k
k
k
3. 3
A.1 Static characteristics
)
(x
f
y
Sensors
x
y
Ko
x
K
y
K - scaling factor in linear systems
)
(x
f - polynomial, exponential, logarithmic function
or experimental determination
)
(x
f -result from modeling of the system (sensor)
-univocal process
4. 4
A.1 Static characteristic
A.2 Invers characteristic (function)
Sensors
x
y
- Perturbative parameters like: humidity, temperature, altitude, ….
i
)
,..
,
( 1 n
x
f
y
i
F = f -1
Sensors
x
y
f
F
]
[
);
1
(
])
[
( 0
0
T
R
C
T
R
]
[
;
)
(
])
[
( 0
0
0 C
R
R
R
R
T
f:
F:
5. 5
]
[
]);
[
],
[
( 1 Hz
C
T
mm
x
f
y o
F = f -1
25
02
.
0
1000
1000
0106
.
0
]
[ 1
2
0
2
y
y
mm
x
])
[
(
1
R
A.1 Static characteristic of complex sensors-Vibrating Wire Jointmeter
A.2 Invers characteristic (function) Vibrating Wire Jointmeter
6. 6
Static conditions
A.1, A.2 e.g.
A.1 Thermistor 1k A.2
A.1 Characteristic processing, linearization
max
max
max
max
min
1
min
1
2
1
2
1
1
;
;
,
,
:
...
;
;
,
,
:
y
y
x
x
y
y
x
x
y
y
x
x
y
y
x
x
n
n
n
n
n
]
,
[
]
,
[
: max
min
max
min y
y
x
x
0
)
(
)
,
(
y
x
y
E
Approximation function of
experimental data
7. 7
Static conditions, example
A.1 GP2Y0A02YK0F A.2
]
55
.
1
8
.
2
[
out
V
]
8
.
0
55
.
1
(
out
V
]
45
.
0
8
.
0
(
out
V
Γ2(Vout)= 119.22 - 52.40 ∙ Vout;
Γ1(Vout)=71.31-20.36∙ Vout ;
Γ3(Vout)= 223.88-183.19∙ Vout
8. 8
Static conditions
A.1, A.2 e.g. GP2Y0A02YK0F
L
L
E C
C
C
3
,
2
,
1
L _ BSLF - Best Straight Line Fit
-Mathematical determination
- Software consideration (Curve expert)
9. 9
Static conditions
A.3 Full Scale input range
Out of range - recalibration, saturate,
- new calibration function
A.4 Full Scale output range
[xmin…xmax]
GP2Y0A02YK0F
)
(x
f
y
)
(x
f
y ]
[ max
min y
y
y
]
45
.
0
8
.
2
[
out
V
GP2Y0A02YK0F
cm
L ]
150
15
[
ymin 0 for xmin = 0, and: ymin = 0 when xmin 0.
x
y f1
f2
f3
f4
X min X max
Y min
y max
10. 10
Static conditions
A.5 Sensitivity
Relative sensitivity
1
2
1
2
x
x
y
y
S
min
max
min
max
x
x
y
y
S
Linear system, K=S
If “K” is higher is better,
but the range is lower.
i
i
x
x
dx
dy
S
Non-linear system
n
x
m
y
II
2
:
order x
m
dx
dy
S
2
[x]
%
;
2
1
m
dx
dy
x
x
S
X
]
[
);
1
(
])
[
(
:
order 0
0
T
R
C
T
R
I
0
R
dT
dR
S
C
0
11. 11
Static conditions
A.5 Sensitivity with external parameters
A.6 Resolution
- sensorial systems with digital unit
- depend by of ADC’s number of bits
)
,..
,
( 1 n
x
f
y
i
i
f
x
x
f
y
i
f
- Parasitic sensitivity
T
K
l
K
T
S
l
l
T
S
T
S
l
R
'
)
1
(
1
)
1
( 0
0
0
0
C
K
m
K
12. 12
Static conditions
A.5 Error-Accuracy
- function approximation,
- Noise,
- Improper device,…
;
,
x x
X
X
x
X
X estimation of x - true value
100
[%]
or
100
[%]
x
x
X
x
x
X
;
0
x
[%]
100
x
X
R
];
[
10
then,
10 6
%
6
% ppm
if ppm
13. 13
Static conditions
A.5.1 Offset Error
y’= f’(x)= f(x)+εoff
A.5.2 Gain Error
y = f(x) linear system
off
x
f
)
0
(
' )
0
(
'
)
(
x
f
x
f
y off
ideal
min
max
min
max
x
x
y
k
y
real
min
max
min
max '
'
'
x
x
y
k
y
k
r
y
r
y
C
C
x
x
y
x
x
y
k
min
max
min
max
min
max
min
max
)
'
'
(
'
, true
14. 14
Static conditions
A.5.3 Non-linear Error
-Caused by approximation
A.5.6 Repeatability Error
..
3
3
2
2
)
(
1
0
)
(
1
0
0
)
(
x
k
x
k
x
g
x
k
k
x
g
x
k
k
i
i
x
i
k
x
f
[%]
100
R
R
15. 15
Problemes
A given sensor has a specified linearity error of 1 % of the
reading plus 0.1 % of the full-scale output (FSO). A second
sensor having the same measurement range has a specified
error of 0.5 % of the reading plus 0.2 % FSO. For what range
of values is the first sensor more accurate than the second
one? If the second sensor had a measurement range twice
that of the first one, for what range of values would it be the
more accurate?
16. 16
Dinamic conditions
)
(
))
(
(
0
t
x
dt
t
y
d
a
k
k
k
pol
s
a
s
a
s
a
s
X
s
Y
s
H
s
X
s
Y
a
s
a
s
a
t
y
a
dt
t
y
d
a
dt
t
y
d
a
L
k
k
k
k
k
k
,
j
s
;
...
1
)
(
)
(
)
(
)
(
)
(
...
)
(
))
(
(
...
))
(
(
0
1
0
1
1
1
1
Exponential Growth
Oscilation
Damped oscillator
Over Damped
17. 17
Dynamic conditions
Potentiometer
Thermistor
)
(
)
( 0 t
x
a
t
y
)
(
)
(
))
(
(
0
1 t
x
t
y
a
dt
t
y
d
a
y
sensitivit
static
1
constant,
time
1
)
(
)
(
)
(
)
(
1
)
(
))
(
(
0
0
1
0
0
1
a
k
a
a
s
k
s
X
s
Y
s
H
t
x
a
t
y
dt
t
y
d
a
a
),
(
1
)
( s
X
s
k
s
Y
1
1
1
)
(
s
k
s
k
s
s
k
s
Y
)
(
)
( 1
s
Y
L
t
y
)
1
(
)
(
t
e
k
t
y
signal
step
unit
/
1
))
(
(
)
( s
t
x
L
s
X
if
zero order
firs order
18. 18
Dynamic conditions
Rising time ( tC )
Response time (tt)
Signal rise
(εM)
)
(
)
(
))
(
(
))
(
(
0
1
2
2
2 t
x
t
y
a
dt
t
y
d
a
dt
t
y
d
a
second order