Products > Test Equipment
REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol
Teneyes:
--- Quote from: NikWing on December 02, 2014, 07:59:21 pm ---I've got a question: how good is the math function of the DS2xxx?
I try to measure current, voltage and multiply both to see the power
on all 3 DSOs all channels and math are set to RMS.
But only the Rigol shows a 10-20W different calculated value
the math also changes with V/div resolution on the Rigol, that doesn't happen on the other 2 DSOs
--- End quote ---
@Nikwing
Please show your display.
Here are some displays of multiply 2 signals
1,2 Multiply using Ax B math
3,4 multiply using Advanced math CH1 x Ch2
5 Shows the Math does not change with different V/div Scale (green is reference before change)
Note: The Math uses the instantaneous values , to get RMS add the calculation in the equation
What FW version is your DSO?
NikWing:
Teneyes, thanks for your reply!
I have to take the screenshots tomorrow, DSO is at work
firmware is 03_00_01_03 I think, that's the file I currently have on my HDD, I think I've seen a newer firmware while browsing this thread yesterday, but had no time to update yet
so I have to go to advanced math and enter some formula?
I'm not sure about the settings on the yokogawa (it displays Vrms, Irms and W/math(1x2)rms on screen), but the on the philips I just went to the math menu, enabled it and selected ch1xch2, both show the same result, just the Rigol shows something else
but well, more details tomorrow :)
Teneyes:
RMS of [ Sin (ch1) x sin(Ch2 - pi/2) ]
Note , using HiRes
Same for FW 00.02.00.01.03, Fw 00.03.00.01.03, and FW 00.03.01.00.04
Teneyes:
Just multiplying positive and negative values
NikWing:
ok, so here it is:
2 screenshots, one from the Yokogawa and the other is from the Rigol.
What I've noticed: if I set math to Ch1xCh2, the displayed value (shows 604W) is a little higher than the value it shows when I set advanced math and enter Ch1 * Ch2 (shows around 596W)
The Yokogawa and Philips both show around 550W
Looks like I can't set something like RMS(CH1) * RMS(CH2) in advanced math.
My problem is, I have to adjust and measure the power of a ballast and I want to achieve the same "accuracy" I have with my workplace DSO (the value is important for a customer)
edit: btw, setting para.save, footer/header on or off has no effect here :o
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