71M6534H Demo Board User’s Manual
Page: 84 of 86
© 2005-2007 TERIDIAN Semiconductor Corporation
V2-0
4.4 FORMULAE FOR FAST CALIBRATION
A method for non-trigonometric derivation of the factors for the fast calibration is shown below.
The phase angle
φ
is calculated as follows:
measured
measured
Wh
VARh
−
=
ϕ
tan
measured
measured
Wh
VARh
−
The value
for tan(
φ
) can be used directly without calculating trigonometric values when
determining the values for
PHAD_n.
We simplify the rather complex term for
PHADJ_n
[
]
[
]
⎥
⎦
⎤
⎢
⎣
⎡
−
−
−
−
−
−
−
+
=
−
−
−
−
)
2
cos(
)
2
1
(
1
)
tan(
)
2
sin(
)
2
1
(
)
2
cos(
)
2
1
(
2
)
2
1
(
1
)
tan(
2
0
9
0
9
0
9
2
9
20
T
f
T
f
T
f
PHADJ
S
S
π
φ
π
π
φ
introduced in Calibration Theory section by substituting the constant parts of it with the variables a, b, and c:
Now we can calculate a, b, and c for 50Hz and for 60Hz, and then insert the values back into the original
equation for
PHADJ
, while at the same time writing 1048576 for 2
20
:
)
2
cos(
)
2
1
(
2
)
2
1
(
1
0
9
2
9
T
f
a
π
⋅
−
−
−
+
=
−
−
)
2
sin(
)
2
1
(
0
9
T
f
b
π
−
−
=
)
2
cos(
)
2
1
(
1
0
9
T
f
c
π
−
−
−
=
measured
measured
measured
measured
Wh
VARh
Wh
VARh
n
PHADJ
−
−
−
=
0131
.
0
1487
.
0
02229
.
0
1048576
_
(for 60Hz metering)
measured
measured
measured
measured
Wh
VARh
Wh
VARh
n
PHADJ
−
−
−
=
09695
.
0
1241
.
0
0155
.
0
1048576
_
(for 50Hz metering)
For the voltage, the ratio of the applied and measured RMS voltages determines the calibration factor:
measured
applied
V
V
VA
CAL
16384
_
=
Содержание 71M6534H
Страница 2: ...71M6534H Demo Board User s Manual Page 2 of 86 2005 2007 TERIDIAN Semiconductor Corporation V2 0...
Страница 8: ...71M6534H Demo Board User s Manual Page 8 of 86 2005 2007 TERIDIAN Semiconductor Corporation V2 0...
Страница 40: ...71M6534H Demo Board User s Manual Page 40 of 86 2005 2007 TERIDIAN Semiconductor Corporation V2 0...
