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REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol
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Teneyes:

--- Quote from: NikWing on December 03, 2014, 09:46:35 am ---The Yokogawa and Philips both show around 550W
Looks like I can't set something like RMS(CH1) * RMS(CH2) in advanced math.

--- End quote ---
Yokogawa    131  x 4.36  = 571.16
      
Rigol      133.8 x 4.523 = 605.1774

The 'Math' multiplication is the same and correct

It looks like the Calculation of RMS is different for the different DSOs
or the measurement technique was different?
See PIx from User's guide


whick is correct??? :-//

Below is display with AxB  and RMS (AxB)
NikWing:
I have no idea :)
I guess I'll use the old DSO until I found out what's making the difference
(I'm no pro, I kinda learn new things by doing it when it's needed)

just an idea: could it be that the Rigol has more points to work with? If I see it correctly, the Yoko just has 10k points for that measurement/calculation and the Rigol way more?
Teneyes:
A point to note with Rigol DS2000 using RMS measurements
watch the GATED AREA

Below are 3 displays of a 1400Hz,  2Vpp Sinewave, which should have a 0.707 RMS voltage:

     1.  Shows RMS =0.708   w/ 102us/div   = equal to 2 full cycles
     2.  Shows RMS =0.681   w/ 114us/div   more then 2 full cycles
     3.  Shows RMS =0.7377  w/ 87.5us/div  less  then 2 full cycles

So with the DSO the RMS calculation depends on display size
and the Yokogawa has 10 divisions
but the  Rigol  has  14 divisions which changes the RMS Calculations

@Nikwing, you may wish to set the Rigol time base to show the same wave as the Yokogawa
   I hope that helps

EDIT: with Square wave a Rigol RMS calculation;  the change depends on DC offset
NikWing:
ahh that makes sense :o

but I think I found the real reason:
I "calibrated" the current clamp and the differential probe I use. For current, I measured 5.00 A(dc) flowing through the current clamp with a multimeter and then compared both values on the DSOs
the Rigol shows 5.12A, so I used advanced math and multiplicated it with something 0.98 and suddently I had the value that I measured with the other 2 DSOs.

for voltage, I measured 130V(ac)/50Hz with the multimeter. Rigol and Yoko both measured 140Vpp.
I set measurements to RMS on both scopes and the Rigol displays 49.5V and the Yoko shows 48.7V (if I calculate it correctly: 1.414*49.5*2 = 139,986, and 137.7V, so the Rigol is much closer to 140)

is it normal that my Rigol measures a higher value than my other DSOs? and is there a way to calibrate it to show the correct value instead of using corrections in math?

and if I may ask that: saving s png screenshot with header, footer and (I currently don't remember the word) the text file enabled doesn't work here. the png looks the same all the time and no txt file is being created. Is that a bug?
Teneyes:

--- Quote from: NikWing on December 04, 2014, 03:52:34 pm ---is it normal that my Rigol measures a higher value than my other DSOs? and is there a way to calibrate it to show the correct value instead of using corrections in math?

--- End quote ---
I am not sure.
Have you preformed the Rigol  'Selfcal"  recently

--- Quote from: NikWing on December 04, 2014, 03:52:34 pm ---if I may ask that: saving s png screenshot with header, footer and (I currently don't remember the word) the text file enabled doesn't work here. the png looks the same all the time and no txt file is being created. Is that a bug?

--- End quote ---
  For screen captures I use Marmad's RUU utility ,Get it Here  . For quick and easy reports with 3-D and animated Gif
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