Y-calibration of HPS50

Instruments Handheld Oscilloscopes
1

Hello!
I have some trouble with HPS50. Measuring of signal, with parameters smaller than 0,5mV/div, display result at very high position and out of screen. Trying move it with X/Y-pos button not give effect - I view only part of signal, not all.
Calibration of Y-pos may help or no? And how it work?

Sorry for my English!

2

Is it possible that there is a DC component to the signal, have you tried using AC coupling?

Your English is very good, no need to apologise!

3

[quote=“cliffyk”]Is it possible that there is a DC component to the signal, have you tried using AC coupling?

Your English is very good, no need to apologise![/quote]
Thanks = ))
Yes, I using DC and AC also, but I need a DC. I test signal like in official documentation on page 18, picture fig.11. Voltage level about 4volt and resolution like at picture (10ys/div, 0,5V/div, markers 64ys, 16,5KHz between) display only lower “tails” of signal. But on documentation picture Y-pos indicator in central position. If I do like that, screen is empty. I trying down Y-pos with buttons and at maximum of lower position not see a full signal.

4

[quote=“SegaBoy”][quote=“cliffyk”]Is it possible that there is a DC component to the signal, have you tried using AC coupling?

Your English is very good, no need to apologise![/quote]
Thanks = ))
Yes, I using DC and AC also, but I need a DC. I test signal like in official documentation on page 18, picture fig.11. Voltage level about 4volt and resolution like at picture (10ys/div, 0,5V/div, markers 64ys, 16,5KHz between) display only lower “tails” of signal. But on documentation picture Y-pos indicator in central position. If I do like that, screen is empty. I trying down Y-pos with buttons and at maximum of lower position not see a full signal.[/quote]

What you describe sounds as though the signal you wish to observe has a DC offset that exceeds the instrument’s Y offset capability–this is what AC coupling is for, to strip the DC component and pass the active signal. The signal shown in Figure 11 (page 18) has no DC offset and is “centered” about ground.

Can you adjust the scope so as to observe the complete waveform when using AC coupling?

If you can then the issue is that the signal of interest is “riding” on a DC offset–this is not an unusual situation in electronic systems as it often allows the system’s work to be done in a more linear portion of the components’ operating range.