p17
Special linearisation
:
For specific applications such as the measurement of volumes, the
meter can memorise an unlinear curve, programmable in X and in Y.
Li.SPE
«
The curve resulting from your equation can be replaced by a series of
linear segments, with a maximum of 20 points
(19 segments).
Note
: the values of the abscisses (x) must go increasing d.in < value of
A01 < value of A02...< An-1.
Example
:
For a layed cylindric tank, 1 meter high (h) and 1 meter long (l); a 0-20
mA linear sensor measures the height of the liquid surface line:
Input to the meter
: height h
0 meters -> 0 mA (empty tank)
1 meter -> 20 mA (full tank)
with cos
β
/2 = ( R - h ) / R
Sin
β
/2 = C/2R
Display of the meter
:
Empty tank volume d.diSP = 0.000
Full tank volume F.diSP =0.785
Volume = L [
π
R²
β
/360 - C(R-h)/2]
Say a curve of 10 equally long segments:
Measure range / number of segments = 20mA/10 = 2mA length of
the segment. For 10 segments nbr = 11.
β
(R)
L (length)
C (chord)
R (ray)
h
(height)
Input
mA
A00 0
A01 2
A02 4
A03 6
A04 8
A05 10
A06 12
A07 14
A08 16
A09 18
A10 20
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.00
73.74
106.26
132.84
156.93
180.00
203.07
227.16
253.74
286.76
360.00
0.00
0.60
0.80
0.92
0.98
1.00
0.98
0.92
0.70
0.60
0.00
0.000
0.041
0.112
0.198
0.293
0.393
0.492
0.587
0.674
0.745
0.785
B00
B01
B02
B03
B04
B05
B06
B07
B08
B09
B10
00.00
01.04
02.85
05.04
07.47
10.00
12.54
14.96
17.17
18.98
20.00
Height
m
Degree
Chord
m
Volume
m3
Outputs
in mA
Programming:
nb = II
Programming from A00 to A10 and from B00 to B10 according to the
table.
0 2 4 6 8 10 12 14 16 18 20
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
20
18
16
14
12
10
8
6
4
2
0.11
0.04
0.20
0.29
0.39
0.49
0.59
0.67
0.75
0.79
volume
in m3
output (mA)
Y
X
input (mA)
height (m)
