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Magtrol Model 6530 Three-Phase Power Analyzer
Chapter 4 – Operating Principles
THEOR
Y
4.2.3
R
OUND
-O
FF
E
RROR
The interrupt routine adds 256 56-bit squared readings. This reading is then divided by 256 and put
into a 24-bit register. Some error occurs during the move to the 24-bit register. The result of the 16-
bit A/D conversion is put into the high 16 bits of a 24-bit register.
Example 1:
A/D reading
= 000B
56-bit register = 00 000B00 000000
(0.0003357)
Square of 56-bit = 00 000000 F20000
(0.00000012269)
Store to 24-bit = 000000
(0.0000000)
Example 2:
A/D reading
= 000C
56-bit register = 00 000C00 000000
(0.0003662)
Square of 56-bit = 00 000001 200000
(0.00000013411)
Store to 24-bit = 000001
4.3
MEASUREMENT MODES
4.3.1
P
EAK
The peak value is defined as the highest value that occurs in the cycle of a repetitive waveform.
The graph below shows one cycle of a repetitive waveform. The peak value is shown. The absolute
value of the reading is used to determine the peak value.
VOLTS vs. ANGLE
-100
-50
0
50
100
150
200
250
0
50
100
150
200
250
300
350
volts
Peak
Figure 4-1 Peak Example
