Rigol 1102E scaling issues

[jerryk]

I have purchased a Rigol 1102E and am confused about the way scaling affects the voltage readings.  Example - If I connect a 9 volt battery and set the scale to 5 volts the voltage reading for the battery is 9.12 vdc.  If I change the scale to 10 volts the voltage reading for the battery is 9.72 vdc.  This kind of voltage variation is typical of all sources of DC/AC across the entire range on the scale dial.  It's hard to tell which reading is real and the variations between each scale setting are considerable on all of the voltage reading available.

I'm new to using oscilloscopes and i think I must be something wrong?  At the moment if I want a true reading for a source I still have fall back on my multimeters which all read consistent and accurate.

Jerry

[tautech]

Welcome to the forum.

As a general rule when using OSD measurements use settings that use as much as possible of the vertical real estate. Some instruments are better than others in this regard but with entry level instruments do not expect DMM accuracy.
On the other hand, in the time domain is where a scope shines. 

[Fungus]

If I connect a 9 volt battery and set the scale to 5 volts the voltage reading for the battery is 9.12 vdc.  If I change the scale to 10 volts the voltage reading for the battery is 9.72 vdc.

Yes, the device will have half the resolution if you double the vertical scale.

For the most accurate measurements try to use as much screen height as possible (the input voltage range is mapped to the screen display).

eg. For a 9V battery use 2V/div.