Rigol DS1054 vertical zero?

[pauledd]

Hi there

I am a very noobish electronics hobbyist and I got my new DS1054.

While getting warm with the new device I am just wondering why I get about 80mV reading Vpp / Vmax with vertical set to 1V and connected nothing else to the scope and default settings. As I go down with the voltage the readings go down too.

Is this expected with oscilloscopes? I know I should not use an oscilloscope as multimeter, but I am just curious about it.

And another observation: I would expect the line sitting right on "0" on the grid if nothing is connected and vertical pos. is reset. But it looks like the line "sits" on top of the vertikal 0V gridline... Let me guess, this is nitpicking? 

[ataradov]

On a totally open probe almost any reading is normal depending on your environment. You need to at least short the probe to ground to get some baseline noise measurement.

I believe the trace offset was fixed in the latest firmware update, but I have not tried it myself. I'm not bothered by small stuff like this.

[pauledd]

Shorting to ground did not help but as you said I should not care on that small stuff.

I just watched a bunch of DS1054 youtube videos and the little vertical offset seems to be common
on all scopes... The vertical label is exactly on zero but the signal "sits" everywhere on top of that...

[nugglix]

First, you should learn to use the built-in screen-capture function.
That photo is close to useless.

[tom66]

Yes, it's normal.

You're seeing the ADC's quantisation and noise floor.

Say the noise floor is 1-2 LSBs at 25'C,  on an 8V range (1V/div, 4 divs either side of zero) that would be 63mVp-p of noise.

So this seems quite normal to me.

[Ducttape]

I think you'll enjoy this video of Dave's.