I am new in the world of hobby electronics, so please excuse any dumb question.
I just bought a PCSGU250 Oscilloscope that connects via USB to my PC.
I have some questions to get started, and worries if the scope is ok or not.
When I input the function generator directly to the Oscilloscope, the values differ,
I tried with a range of different settings, and the result seems to be the same.
The function generator outputs for example (at multiple frequencies) a signal with the amplitute of 3 volts, the scope tells me it is only 1.5 volts.
I tried as well the X10 switch on the probe, but this makes the result worse (around 10 times, as the switch implies, which sounds like it should work like this)
A secondary question I have as well, as the software only goes up to only 3 volts, and my signal in my circuit is up to 9 volts, is it harmfull to measure this? (the scope itself says max input=30v, so I assume not, but I am not sure because of the different scales in the software and hardware, which is the valid one)
You may use the View menu options to display various parameters on the screen e.g. the RMS value.
You may also use the View menu option “Markers” to measure the amplitude and time on the screen using the cursors.
Please see the “Help” menu for more details.
Using the probe setting x1 you can measure voltages up to 24V (3V/div) and using the probe setting x10 up to 240V (30V/div).
Select the “Probe” button on the screen according to the probe x1/x10 attenuator setting. Doing this you get correct measurement readings.
You may also use the View menu option “Waveform Parameters” to check various properties of the signal.
Thanks for the quick reply, unfortuanatly I had some issue with my USB port that I needed to resolve before I could do any more tests.
With the exact same settings as in the screenshot, I got the following results (I have a screenshot, in case of doubt, but I am not sure how to insert it into this post)
VRMS=3.45 volt in the scope, and 3 in the function generator (btw, what is VRMS, I tried googling it, but to no real help)
dV=9.84 on the scope, and 8.49 inside the function generator.
At least the results are now recognisable. Perhaps the rest is up to calibration?
Regarding this, when I calibrate, it says, make sure the probe is not connected to any external circuit. Does this also include the generator?
It seems that you are using the original software version from the CD.
You can download the latest PCLAB2000LT version 1.09.
The generator accuracy is improved in this version.
Here is the link to the downloads page: velleman.eu/distributor/supp … U250&type=
From the same page you can download the driver package too.
When extracted you get two subfolders.
In Windows Vista and in Windows 7 please use the driver in the subfolder: PCSGU250Driver_WinUSB
Here you can download the instructions how to update the driver: box.net/shared/66aei7j31s
The calibration concerns only the oscilloscope.
There is Fine Tune option for the generator in the Options menu.
[quote=“chaos51”]Great, now it looks more like the screenshot you’ve shown. Vrms=2.97 and Dv=8.53.
Thanks a bunch for the help![/quote]
BTW, “dV” is “delta” Voltage, I.e. the difference in voltage levels between the cursors.
In general engineering the upper case Greek letter “Δ” (Delta) is used to indicate the difference of two values, however as the Greek letter is often rendered differently by some character sets, it is not uncommon to see the lowercase “d” used in its stead…
