MR8740、MR8741_user_manual_eng_20191016H.pdf - 第251页

10.3 Waveform Calculation Operators and Results 239 9 Chapter 10 W aveform Calculation Functions 10 First integral (INT) Second integral (INT2) First and second integrals are calculated usi ng the trapezoidal rule. d 1 t…

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10.3 Waveform Calculation Operators and Results
238
Arccosine (ACOS)
When d
i
> 1, b
i
= 0
When -1
d
i
1, b
i
= acos(d
i
)
When d
i
< -1 , b
i
=
(i = 1, 2, .... n)
Trigonometric functions employ radian (rad) units.
Arctangent (ATAN)
b
i
= atan(d
i
) (i = 1, 2, .... n)
Trigonometric functions employ radian (rad) units.
First derivative (DIF)
Second derivative (DIF2)
The first and second derivative calculations use a fifth-order Lagrange interpolation poly-
nomial to obtain a point data value from five sequential points.
d
1
to d
n
are the derivatives calculated for sample times t
1
to t
n
.
Note: Scattering of calculation results increases as input voltage level decreases. If scat-
tering is excessive, apply the moving average (MOV).
Calculation formulas for the first derivative
Point t
1
b
1
= (-25d
1
+ 48d
2
- 36d
3
+ 16d
4
- 3d
5
)/ 12h
Point t
2
b
2
= (-3d
1
- 10d
2
+ 18d
3
- 6d
4
+ d
5
)/ 12h
Point t
3
b
3
= (d
1
- 8d
2
+ 8d
4
- d
5
)/ 12h
Point t
i
b
i
= (d
i -2
- 8d
i-1
+ 8d
i+1
- d
i+2
)/ 12h
Point t
n-2
b
n-2
= (d
n-4
- 8d
n-3
+ 8d
n-1
-d
n
)/12h
Point t
n-1
b
n-1
= (-d
n-4
+ 6d
n-3
- 18d
n-2
+ 10d
n-1
+ 3d
n
)/12h
Point t
n
b
n
= (3d
n-4
- 16d
n-3
+ 36d
n-2
- 48d
n-1
+ 25d
n
)/12h
b
1
to b
n
: calculation results
h =
t : Sampling Period
Calculation formulas for the second derivative
Point t
1
b
1
= (35d
1
- 104d
2
+ 114d
3
- 56d
4
+ 11d
5
)/12h
2
Point t
2
b
2
= (11d
1
- 20d
2
+ 6d
3
+ 4d
4
- d
5
)/12h
2
Point t
3
b
3
= (-d
1
+ 16d
2
-30d
3
+ 16d
4
- d
5
)/12h
2
Point t
i
b
i
= (-d
i-2
+ 16d
i-1
- 30d
i
+ 16d
i+1
- d
i+2
)/12h
2
Point t
n-2
b
n-2
= (-d
n-4
+ 16d
n-3
- 30d
n-2
+ 16d
n-1
- d
n
)/12h
2
Point t
n-1
b
n-1
= (-d
n-4
+ 4d
n-3
+ 6d
n-2
- 20d
n-1
+ 11d
n
)/12h
2
Point t
n
b
n
= (11d
n-4
-56d
n-3
+ 114d
n-2
- 104d
n-1
+ 35d
n
)/12h
2
b
i
: ith member of calculation result data, d
i
: ith member of source channel data
Waveform Calculation Type Description
10.3 Waveform Calculation Operators and Results
239
9
Chapter 10 Waveform Calculation Functions
10
First integral (INT)
Second integral (INT2)
First and second integrals are calculated using the trapezoidal rule.
d
1
to d
n
are the integrals calculated for sample times t
1
to t
n
.
Calculation formulas for the first integral
Point t
1
I
1
= 0
Point t
2
I
2
= (d
1
+ d
2
)h/2
Point t
3
I
3
= (d
1
+ d
2
)h/2 + (d
2
+ d
3
)h/2 = I
2
+ (d
2
+ d
3
)h/2
Point t
n
I
n
= I
n-1
+ (d
n-1
+ d
n
)h/2
I
1
to I
n
: calculation results
h =
t: Sampling Period
Calculation formulas for the second integral
Point t
1
II
1
= 0
Point t
2
II
2
= (I
1
+ I
2
)h/2
Point t
3
II
3
= (I
1
+ I
2
)h/2 + (I
2
+ I
3
)h/2 = II
2
+ (I
2
+ I
3
)h/2
Point t
n
II
n
= II
n-1
+ (I
n-1
+ I
n
)h/2
II
1
to II
n
: calculation results
Digital Voltmeter Unit
PLC delay time shift
(PLCS)
Shifts the time by the amount of delay for the frequency (PLC) and NPLC set on MR8990
Digital Voltmeter Unit.
Since the Digital Voltmeter Unit obtains the average of the amount of time set for NPLC,
a waveform that is delayed by just a time that is 1/2 of the NPLC is observed, compared
to 8966 Analog Unit. The PLCS calculation shifts this amount of delay time to correct the
offset with the analog unit.
Reference: If there is no data at the end of the calculation result, the voltage becomes 0
V.
b
i
: ith member of calculation result data, d
i
: ith member of source channel data
Waveform Calculation Type Description
10.3 Waveform Calculation Operators and Results
240