GW Instek APS-1102A User Manual - Manual (Page 84)

APS-1102A User Manual
APS-1102A 4-12
b) Calculation method of the measurement values
Output voltage and current are sampled and A/D converted at 50 kS/s in general or at 5 kS/s when
a sequence program is running. The frequency bandwidth of each analog circuit from a voltage or
current point to the A/D converter is 50 kHz.
RMS, average and peak values of voltage or current and active power values are calculated with
following formulas and sampled values over integer multiples of their periods nearest to 100 ms.
The following values are used as the periods: frequency setting values in INT/ADD modes,
synchronization frequency measurements in SYNC modes, and fixed values to 100 ms in EXT
modes or when the frequency is lower than 10 Hz in any mode.
RMS voltage:
    


 
1
0
2
1
N
n
rms
n V
N
V RMS current:
    


 
1
0
2
1
N
n
rms
n I
N
I
DC average voltage:
  


 
1
0
arg
1
N
n
n V
N
V DC average current:
  


 
1
0
arg
1
N
n
n I
N
I
Max voltage:
   
n V MAX V
peak


Min voltage:
   
n V MIN V
peak


Max current:
   
n I MAX I
peak


Min current：
   
n I MIN I
peak


Active power:
      


  
1
0
1
N
n
n I n V
N
W
However,
 
n V ,
 
n I : sample output voltage/current measurement data
N : Number of samples.
Apparent power, reactive power, crest factor and peak current hold are calculated from equations
below using previous calculated values.
Apparent power:
rms rms
I V VA
 
Reactive power:
 
2 2
var W VA
 
Power factor:
VA
W
PF

Crest factor:
 
rms
peak peak
I
I I MAX
CF
  
,
Current peak hold:
 
 

peak peak ph
I I MAX hold I ,